From a04c6dac5caa54798c023474a6e76f1ec9b9aa2d Mon Sep 17 00:00:00 2001 From: Milan Zamazal Date: Wed, 11 Jul 2018 13:02:55 +0100 Subject: [PATCH 1/1] Import stockfish_9.orig.tar.gz [dgit import orig stockfish_9.orig.tar.gz] --- .travis.yml | 73 ++ AUTHORS | 98 +++ Copying.txt | 674 +++++++++++++++ Readme.md | 123 +++ Top CPU Contributors.txt | 132 +++ appveyor.yml | 71 ++ src/Makefile | 560 +++++++++++++ src/benchmark.cpp | 156 ++++ src/bitbase.cpp | 180 ++++ src/bitboard.cpp | 326 ++++++++ src/bitboard.h | 339 ++++++++ src/endgame.cpp | 816 ++++++++++++++++++ src/endgame.h | 125 +++ src/evaluate.cpp | 952 +++++++++++++++++++++ src/evaluate.h | 41 + src/main.cpp | 55 ++ src/material.cpp | 228 +++++ src/material.h | 73 ++ src/misc.cpp | 317 +++++++ src/misc.h | 112 +++ src/movegen.cpp | 420 ++++++++++ src/movegen.h | 75 ++ src/movepick.cpp | 334 ++++++++ src/movepick.h | 151 ++++ src/pawns.cpp | 299 +++++++ src/pawns.h | 90 ++ src/position.cpp | 1213 +++++++++++++++++++++++++++ src/position.h | 427 ++++++++++ src/psqt.cpp | 126 +++ src/search.cpp | 1653 ++++++++++++++++++++++++++++++++++++ src/search.h | 106 +++ src/syzygy/tbprobe.cpp | 1702 ++++++++++++++++++++++++++++++++++++++ src/syzygy/tbprobe.h | 79 ++ src/thread.cpp | 199 +++++ src/thread.h | 123 +++ src/thread_win32.h | 70 ++ src/timeman.cpp | 132 +++ src/timeman.h | 48 ++ src/tt.cpp | 118 +++ src/tt.h | 121 +++ src/types.h | 466 +++++++++++ src/uci.cpp | 316 +++++++ src/uci.h | 80 ++ src/ucioption.cpp | 164 ++++ tests/instrumented.sh | 123 +++ tests/perft.sh | 32 + tests/reprosearch.sh | 61 ++ tests/signature.sh | 27 + 48 files changed, 14206 insertions(+) create mode 100644 .travis.yml create mode 100644 AUTHORS create mode 100644 Copying.txt create mode 100644 Readme.md create mode 100644 Top CPU Contributors.txt create mode 100644 appveyor.yml create mode 100644 src/Makefile create mode 100644 src/benchmark.cpp create mode 100644 src/bitbase.cpp create mode 100644 src/bitboard.cpp create mode 100644 src/bitboard.h create mode 100644 src/endgame.cpp create mode 100644 src/endgame.h create mode 100644 src/evaluate.cpp create mode 100644 src/evaluate.h create mode 100644 src/main.cpp create mode 100644 src/material.cpp create mode 100644 src/material.h create mode 100644 src/misc.cpp create mode 100644 src/misc.h create mode 100644 src/movegen.cpp create mode 100644 src/movegen.h create mode 100644 src/movepick.cpp create mode 100644 src/movepick.h create mode 100644 src/pawns.cpp create mode 100644 src/pawns.h create mode 100644 src/position.cpp create mode 100644 src/position.h create mode 100644 src/psqt.cpp create mode 100644 src/search.cpp create mode 100644 src/search.h create mode 100644 src/syzygy/tbprobe.cpp create mode 100644 src/syzygy/tbprobe.h create mode 100644 src/thread.cpp create mode 100644 src/thread.h create mode 100644 src/thread_win32.h create mode 100644 src/timeman.cpp create mode 100644 src/timeman.h create mode 100644 src/tt.cpp create mode 100644 src/tt.h create mode 100644 src/types.h create mode 100644 src/uci.cpp create mode 100644 src/uci.h create mode 100644 src/ucioption.cpp create mode 100755 tests/instrumented.sh create mode 100755 tests/perft.sh create mode 100755 tests/reprosearch.sh create mode 100755 tests/signature.sh diff --git a/.travis.yml b/.travis.yml new file mode 100644 index 0000000..8586921 --- /dev/null +++ b/.travis.yml @@ -0,0 +1,73 @@ +language: cpp +sudo: required +dist: trusty + +matrix: + include: + - os: linux + compiler: gcc + addons: + apt: + sources: ['ubuntu-toolchain-r-test'] + packages: ['g++-6', 'g++-6-multilib', 'g++-multilib', 'valgrind', 'expect'] + env: + - COMPILER=g++-6 + - COMP=gcc + + - os: linux + compiler: clang + addons: + apt: + sources: ['ubuntu-toolchain-r-test'] + packages: ['clang', 'g++-multilib', 'valgrind', 'expect'] + env: + - COMPILER=clang++ + - COMP=clang + + - os: osx + compiler: gcc + env: + - COMPILER=g++ + - COMP=gcc + + - os: osx + compiler: clang + env: + - COMPILER=clang++ V='Apple LLVM 6.0' # Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) + - COMP=clang + +branches: + only: + - master + +before_script: + - cd src + +script: + # Obtain bench reference from git log + - git log HEAD | grep "\b[Bb]ench[ :]\+[0-9]\{7\}" | head -n 1 | sed "s/[^0-9]*\([0-9][0-9]*\)/\1/g" > git_sig + - export benchref=$(cat git_sig) + - echo "Reference bench:" $benchref + # + # Verify bench number against various builds + - export CXXFLAGS=-Werror + - make clean && make -j2 ARCH=x86-64 optimize=no debug=yes build && ../tests/signature.sh $benchref + - make clean && make -j2 ARCH=x86-32 optimize=no debug=yes build && ../tests/signature.sh $benchref + - make clean && make -j2 ARCH=x86-32 build && ../tests/signature.sh $benchref + - make clean && make -j2 ARCH=x86-64 build && ../tests/signature.sh $benchref + # + # Check perft and reproducible search + - ../tests/perft.sh + - ../tests/reprosearch.sh + # + # Valgrind + # + - export CXXFLAGS=-O1 + - if [ -x "$(command -v valgrind )" ]; then make clean && make -j2 ARCH=x86-64 debug=yes optimize=no build > /dev/null && ../tests/instrumented.sh --valgrind; fi + - if [ -x "$(command -v valgrind )" ]; then ../tests/instrumented.sh --valgrind-thread; fi + # + # Sanitizer + # + # Use g++-6 as a proxy for having sanitizers, might need revision as they become available for more recent versions of clang/gcc + - if [[ "$COMPILER" == "g++-6" ]]; then make clean && make -j2 ARCH=x86-64 sanitize=undefined optimize=no debug=yes build > /dev/null && ../tests/instrumented.sh --sanitizer-undefined; fi + - if [[ "$COMPILER" == "g++-6" ]]; then make clean && make -j2 ARCH=x86-64 sanitize=thread optimize=no debug=yes build > /dev/null && ../tests/instrumented.sh --sanitizer-thread; fi diff --git a/AUTHORS b/AUTHORS new file mode 100644 index 0000000..9b91b93 --- /dev/null +++ b/AUTHORS @@ -0,0 +1,98 @@ +# Generated with 'git shortlog -sn | cut -c8-', which sorts by commits, manually ordered the first four authors, merged duplicates + +Tord Romstad +Marco Costalba (mcostalba) +Joona Kiiski (zamar) +Gary Linscott (glinscott) +Lucas Braesch (lucasart) +Bill Henry (VoyagerOne) +mstembera +Stéphane Nicolet (Stephane Nicolet, snicolet) +Stefan Geschwentner +Alain SAVARD (Rocky640) +Jörg Oster (Joerg Oster, joergoster) +Reuven Peleg +Chris Caino (Chris Cain, ceebo) +Jean-Francois Romang +homoSapiensSapiens +Leonid Pechenik +Stefano Cardanobile (Stefano80) +Arjun Temurnikar +Uri Blass (uriblass) +jundery +Ajith (ajithcj) +hxim +Ralph Stößer (Ralph Stoesser) +Guenther Demetz +Jonathan Calovski (Mysseno) +Tom Vijlbrief +mbootsector +Daylen Yang +ElbertoOne +Henri Wiechers +loco-loco +Joost VandeVondele (Joost Vandevondele) +Ronald de Man (syzygy) +DU-jdto +David Zar +Eelco de Groot +Jerry Donald +NicklasPersson +Ryan Schmitt +Alexander Kure +Dan Schmidt +H. Felix Wittmann +Jacques +Joseph R. Prostko +Justin Blanchard +Linus Arver +Luca Brivio +Lyudmil Antonov +Rodrigo Exterckötter Tjäder +Ron Britvich +RyanTaker +Vince Negri +erbsenzaehler +Joseph Hellis (jhellis3) +shane31 +Andrew Grant +Andy Duplain +Auguste Pop +Balint Pfliegel +Dariusz Orzechowski +DiscanX +Ernesto Gatti +Gregor Cramer +Hiraoka Takuya (HiraokaTakuya) +Hongzhi Cheng +IIvec +Kelly Wilson +Ken T Takusagawa +Kojirion +Krgp +Matt Sullivan +Matthew Lai +Matthew Sullivan +Michel Van den Bergh +Niklas Fiekas +Oskar Werkelin Ahlin +Pablo Vazquez +Pascal Romaret +Raminder Singh +Richard Lloyd +Ryan Takker +Thanar2 +absimaldata +atumanian +braich +fanon +gamander +gguliash +kinderchocolate +pellanda +ppigazzini +renouve +sf-x +thaspel +unknown + diff --git a/Copying.txt b/Copying.txt new file mode 100644 index 0000000..818433e --- /dev/null +++ b/Copying.txt @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. We, the Free Software Foundation, use the +GNU General Public License for most of our software; it applies also to +any other work released this way by its authors. You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +them if you wish), that you receive source code or can get it if you +want it, that you can change the software or use pieces of it in new +free programs, and that you know you can do these things. + + To protect your rights, we need to prevent others from denying you +these rights or asking you to surrender the rights. Therefore, you have +certain responsibilities if you distribute copies of the software, or if +you modify it: responsibilities to respect the freedom of others. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must pass on to the recipients the same +freedoms that you received. You must make sure that they, too, receive +or can get the source code. And you must show them these terms so they +know their rights. + + Developers that use the GNU GPL protect your rights with two steps: +(1) assert copyright on the software, and (2) offer you this License +giving you legal permission to copy, distribute and/or modify it. + + For the developers' and authors' protection, the GPL clearly explains +that there is no warranty for this free software. For both users' and +authors' sake, the GPL requires that modified versions be marked as +changed, so that their problems will not be attributed erroneously to +authors of previous versions. + + Some devices are designed to deny users access to install or run +modified versions of the software inside them, although the manufacturer +can do so. This is fundamentally incompatible with the aim of +protecting users' freedom to change the software. The systematic +pattern of such abuse occurs in the area of products for individuals to +use, which is precisely where it is most unacceptable. Therefore, we +have designed this version of the GPL to prohibit the practice for those +products. If such problems arise substantially in other domains, we +stand ready to extend this provision to those domains in future versions +of the GPL, as needed to protect the freedom of users. + + Finally, every program is threatened constantly by software patents. +States should not allow patents to restrict development and use of +software on general-purpose computers, but in those that do, we wish to +avoid the special danger that patents applied to a free program could +make it effectively proprietary. To prevent this, the GPL assures that +patents cannot be used to render the program non-free. + + The precise terms and conditions for copying, distribution and +modification follow. + + TERMS AND CONDITIONS + + 0. Definitions. + + "This License" refers to version 3 of the GNU General Public License. + + "Copyright" also means copyright-like laws that apply to other kinds of +works, such as semiconductor masks. + + "The Program" refers to any copyrightable work licensed under this +License. Each licensee is addressed as "you". "Licensees" and +"recipients" may be individuals or organizations. + + To "modify" a work means to copy from or adapt all or part of the work +in a fashion requiring copyright permission, other than the making of an +exact copy. The resulting work is called a "modified version" of the +earlier work or a work "based on" the earlier work. + + A "covered work" means either the unmodified Program or a work based +on the Program. + + To "propagate" a work means to do anything with it that, without +permission, would make you directly or secondarily liable for +infringement under applicable copyright law, except executing it on a +computer or modifying a private copy. Propagation includes copying, +distribution (with or without modification), making available to the +public, and in some countries other activities as well. + + To "convey" a work means any kind of propagation that enables other +parties to make or receive copies. Mere interaction with a user through +a computer network, with no transfer of a copy, is not conveying. + + An interactive user interface displays "Appropriate Legal Notices" +to the extent that it includes a convenient and prominently visible +feature that (1) displays an appropriate copyright notice, and (2) +tells the user that there is no warranty for the work (except to the +extent that warranties are provided), that licensees may convey the +work under this License, and how to view a copy of this License. If +the interface presents a list of user commands or options, such as a +menu, a prominent item in the list meets this criterion. + + 1. Source Code. + + The "source code" for a work means the preferred form of the work +for making modifications to it. "Object code" means any non-source +form of a work. + + A "Standard Interface" means an interface that either is an official +standard defined by a recognized standards body, or, in the case of +interfaces specified for a particular programming language, one that +is widely used among developers working in that language. + + The "System Libraries" of an executable work include anything, other +than the work as a whole, that (a) is included in the normal form of +packaging a Major Component, but which is not part of that Major +Component, and (b) serves only to enable use of the work with that +Major Component, or to implement a Standard Interface for which an +implementation is available to the public in source code form. A +"Major Component", in this context, means a major essential component +(kernel, window system, and so on) of the specific operating system +(if any) on which the executable work runs, or a compiler used to +produce the work, or an object code interpreter used to run it. + + The "Corresponding Source" for a work in object code form means all +the source code needed to generate, install, and (for an executable +work) run the object code and to modify the work, including scripts to +control those activities. However, it does not include the work's +System Libraries, or general-purpose tools or generally available free +programs which are used unmodified in performing those activities but +which are not part of the work. For example, Corresponding Source +includes interface definition files associated with source files for +the work, and the source code for shared libraries and dynamically +linked subprograms that the work is specifically designed to require, +such as by intimate data communication or control flow between those +subprograms and other parts of the work. + + The Corresponding Source need not include anything that users +can regenerate automatically from other parts of the Corresponding +Source. + + The Corresponding Source for a work in source code form is that +same work. + + 2. Basic Permissions. + + All rights granted under this License are granted for the term of +copyright on the Program, and are irrevocable provided the stated +conditions are met. This License explicitly affirms your unlimited +permission to run the unmodified Program. The output from running a +covered work is covered by this License only if the output, given its +content, constitutes a covered work. This License acknowledges your +rights of fair use or other equivalent, as provided by copyright law. + + You may make, run and propagate covered works that you do not +convey, without conditions so long as your license otherwise remains +in force. You may convey covered works to others for the sole purpose +of having them make modifications exclusively for you, or provide you +with facilities for running those works, provided that you comply with +the terms of this License in conveying all material for which you do +not control copyright. Those thus making or running the covered works +for you must do so exclusively on your behalf, under your direction +and control, on terms that prohibit them from making any copies of +your copyrighted material outside their relationship with you. + + Conveying under any other circumstances is permitted solely under +the conditions stated below. Sublicensing is not allowed; section 10 +makes it unnecessary. + + 3. Protecting Users' Legal Rights From Anti-Circumvention Law. + + No covered work shall be deemed part of an effective technological +measure under any applicable law fulfilling obligations under article +11 of the WIPO copyright treaty adopted on 20 December 1996, or +similar laws prohibiting or restricting circumvention of such +measures. + + When you convey a covered work, you waive any legal power to forbid +circumvention of technological measures to the extent such circumvention +is effected by exercising rights under this License with respect to +the covered work, and you disclaim any intention to limit operation or +modification of the work as a means of enforcing, against the work's +users, your or third parties' legal rights to forbid circumvention of +technological measures. + + 4. Conveying Verbatim Copies. + + You may convey verbatim copies of the Program's source code as you +receive it, in any medium, provided that you conspicuously and +appropriately publish on each copy an appropriate copyright notice; +keep intact all notices stating that this License and any +non-permissive terms added in accord with section 7 apply to the code; +keep intact all notices of the absence of any warranty; and give all +recipients a copy of this License along with the Program. + + You may charge any price or no price for each copy that you convey, +and you may offer support or warranty protection for a fee. + + 5. Conveying Modified Source Versions. + + You may convey a work based on the Program, or the modifications to +produce it from the Program, in the form of source code under the +terms of section 4, provided that you also meet all of these conditions: + + a) The work must carry prominent notices stating that you modified + it, and giving a relevant date. + + b) The work must carry prominent notices stating that it is + released under this License and any conditions added under section + 7. This requirement modifies the requirement in section 4 to + "keep intact all notices". + + c) You must license the entire work, as a whole, under this + License to anyone who comes into possession of a copy. This + License will therefore apply, along with any applicable section 7 + additional terms, to the whole of the work, and all its parts, + regardless of how they are packaged. This License gives no + permission to license the work in any other way, but it does not + invalidate such permission if you have separately received it. + + d) If the work has interactive user interfaces, each must display + Appropriate Legal Notices; however, if the Program has interactive + interfaces that do not display Appropriate Legal Notices, your + work need not make them do so. + + A compilation of a covered work with other separate and independent +works, which are not by their nature extensions of the covered work, +and which are not combined with it such as to form a larger program, +in or on a volume of a storage or distribution medium, is called an +"aggregate" if the compilation and its resulting copyright are not +used to limit the access or legal rights of the compilation's users +beyond what the individual works permit. Inclusion of a covered work +in an aggregate does not cause this License to apply to the other +parts of the aggregate. + + 6. Conveying Non-Source Forms. + + You may convey a covered work in object code form under the terms +of sections 4 and 5, provided that you also convey the +machine-readable Corresponding Source under the terms of this License, +in one of these ways: + + a) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by the + Corresponding Source fixed on a durable physical medium + customarily used for software interchange. + + b) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by a + written offer, valid for at least three years and valid for as + long as you offer spare parts or customer support for that product + model, to give anyone who possesses the object code either (1) a + copy of the Corresponding Source for all the software in the + product that is covered by this License, on a durable physical + medium customarily used for software interchange, for a price no + more than your reasonable cost of physically performing this + conveying of source, or (2) access to copy the + Corresponding Source from a network server at no charge. + + c) Convey individual copies of the object code with a copy of the + written offer to provide the Corresponding Source. This + alternative is allowed only occasionally and noncommercially, and + only if you received the object code with such an offer, in accord + with subsection 6b. + + d) Convey the object code by offering access from a designated + place (gratis or for a charge), and offer equivalent access to the + Corresponding Source in the same way through the same place at no + further charge. You need not require recipients to copy the + Corresponding Source along with the object code. If the place to + copy the object code is a network server, the Corresponding Source + may be on a different server (operated by you or a third party) + that supports equivalent copying facilities, provided you maintain + clear directions next to the object code saying where to find the + Corresponding Source. Regardless of what server hosts the + Corresponding Source, you remain obligated to ensure that it is + available for as long as needed to satisfy these requirements. + + e) Convey the object code using peer-to-peer transmission, provided + you inform other peers where the object code and Corresponding + Source of the work are being offered to the general public at no + charge under subsection 6d. + + A separable portion of the object code, whose source code is excluded +from the Corresponding Source as a System Library, need not be +included in conveying the object code work. + + A "User Product" is either (1) a "consumer product", which means any +tangible personal property which is normally used for personal, family, +or household purposes, or (2) anything designed or sold for incorporation +into a dwelling. In determining whether a product is a consumer product, +doubtful cases shall be resolved in favor of coverage. For a particular +product received by a particular user, "normally used" refers to a +typical or common use of that class of product, regardless of the status +of the particular user or of the way in which the particular user +actually uses, or expects or is expected to use, the product. A product +is a consumer product regardless of whether the product has substantial +commercial, industrial or non-consumer uses, unless such uses represent +the only significant mode of use of the product. + + "Installation Information" for a User Product means any methods, +procedures, authorization keys, or other information required to install +and execute modified versions of a covered work in that User Product from +a modified version of its Corresponding Source. The information must +suffice to ensure that the continued functioning of the modified object +code is in no case prevented or interfered with solely because +modification has been made. + + If you convey an object code work under this section in, or with, or +specifically for use in, a User Product, and the conveying occurs as +part of a transaction in which the right of possession and use of the +User Product is transferred to the recipient in perpetuity or for a +fixed term (regardless of how the transaction is characterized), the +Corresponding Source conveyed under this section must be accompanied +by the Installation Information. But this requirement does not apply +if neither you nor any third party retains the ability to install +modified object code on the User Product (for example, the work has +been installed in ROM). + + The requirement to provide Installation Information does not include a +requirement to continue to provide support service, warranty, or updates +for a work that has been modified or installed by the recipient, or for +the User Product in which it has been modified or installed. Access to a +network may be denied when the modification itself materially and +adversely affects the operation of the network or violates the rules and +protocols for communication across the network. + + Corresponding Source conveyed, and Installation Information provided, +in accord with this section must be in a format that is publicly +documented (and with an implementation available to the public in +source code form), and must require no special password or key for +unpacking, reading or copying. + + 7. Additional Terms. + + "Additional permissions" are terms that supplement the terms of this +License by making exceptions from one or more of its conditions. +Additional permissions that are applicable to the entire Program shall +be treated as though they were included in this License, to the extent +that they are valid under applicable law. If additional permissions +apply only to part of the Program, that part may be used separately +under those permissions, but the entire Program remains governed by +this License without regard to the additional permissions. + + When you convey a copy of a covered work, you may at your option +remove any additional permissions from that copy, or from any part of +it. (Additional permissions may be written to require their own +removal in certain cases when you modify the work.) You may place +additional permissions on material, added by you to a covered work, +for which you have or can give appropriate copyright permission. + + Notwithstanding any other provision of this License, for material you +add to a covered work, you may (if authorized by the copyright holders of +that material) supplement the terms of this License with terms: + + a) Disclaiming warranty or limiting liability differently from the + terms of sections 15 and 16 of this License; or + + b) Requiring preservation of specified reasonable legal notices or + author attributions in that material or in the Appropriate Legal + Notices displayed by works containing it; or + + c) Prohibiting misrepresentation of the origin of that material, or + requiring that modified versions of such material be marked in + reasonable ways as different from the original version; or + + d) Limiting the use for publicity purposes of names of licensors or + authors of the material; or + + e) Declining to grant rights under trademark law for use of some + trade names, trademarks, or service marks; or + + f) Requiring indemnification of licensors and authors of that + material by anyone who conveys the material (or modified versions of + it) with contractual assumptions of liability to the recipient, for + any liability that these contractual assumptions directly impose on + those licensors and authors. + + All other non-permissive additional terms are considered "further +restrictions" within the meaning of section 10. If the Program as you +received it, or any part of it, contains a notice stating that it is +governed by this License along with a term that is a further +restriction, you may remove that term. If a license document contains +a further restriction but permits relicensing or conveying under this +License, you may add to a covered work material governed by the terms +of that license document, provided that the further restriction does +not survive such relicensing or conveying. + + If you add terms to a covered work in accord with this section, you +must place, in the relevant source files, a statement of the +additional terms that apply to those files, or a notice indicating +where to find the applicable terms. + + Additional terms, permissive or non-permissive, may be stated in the +form of a separately written license, or stated as exceptions; +the above requirements apply either way. + + 8. Termination. + + You may not propagate or modify a covered work except as expressly +provided under this License. Any attempt otherwise to propagate or +modify it is void, and will automatically terminate your rights under +this License (including any patent licenses granted under the third +paragraph of section 11). + + However, if you cease all violation of this License, then your +license from a particular copyright holder is reinstated (a) +provisionally, unless and until the copyright holder explicitly and +finally terminates your license, and (b) permanently, if the copyright +holder fails to notify you of the violation by some reasonable means +prior to 60 days after the cessation. + + Moreover, your license from a particular copyright holder is +reinstated permanently if the copyright holder notifies you of the +violation by some reasonable means, this is the first time you have +received notice of violation of this License (for any work) from that +copyright holder, and you cure the violation prior to 30 days after +your receipt of the notice. + + Termination of your rights under this section does not terminate the +licenses of parties who have received copies or rights from you under +this License. If your rights have been terminated and not permanently +reinstated, you do not qualify to receive new licenses for the same +material under section 10. + + 9. Acceptance Not Required for Having Copies. + + You are not required to accept this License in order to receive or +run a copy of the Program. Ancillary propagation of a covered work +occurring solely as a consequence of using peer-to-peer transmission +to receive a copy likewise does not require acceptance. However, +nothing other than this License grants you permission to propagate or +modify any covered work. These actions infringe copyright if you do +not accept this License. Therefore, by modifying or propagating a +covered work, you indicate your acceptance of this License to do so. + + 10. Automatic Licensing of Downstream Recipients. + + Each time you convey a covered work, the recipient automatically +receives a license from the original licensors, to run, modify and +propagate that work, subject to this License. You are not responsible +for enforcing compliance by third parties with this License. + + An "entity transaction" is a transaction transferring control of an +organization, or substantially all assets of one, or subdividing an +organization, or merging organizations. If propagation of a covered +work results from an entity transaction, each party to that +transaction who receives a copy of the work also receives whatever +licenses to the work the party's predecessor in interest had or could +give under the previous paragraph, plus a right to possession of the +Corresponding Source of the work from the predecessor in interest, if +the predecessor has it or can get it with reasonable efforts. + + You may not impose any further restrictions on the exercise of the +rights granted or affirmed under this License. For example, you may +not impose a license fee, royalty, or other charge for exercise of +rights granted under this License, and you may not initiate litigation +(including a cross-claim or counterclaim in a lawsuit) alleging that +any patent claim is infringed by making, using, selling, offering for +sale, or importing the Program or any portion of it. + + 11. Patents. + + A "contributor" is a copyright holder who authorizes use under this +License of the Program or a work on which the Program is based. The +work thus licensed is called the contributor's "contributor version". + + A contributor's "essential patent claims" are all patent claims +owned or controlled by the contributor, whether already acquired or +hereafter acquired, that would be infringed by some manner, permitted +by this License, of making, using, or selling its contributor version, +but do not include claims that would be infringed only as a +consequence of further modification of the contributor version. For +purposes of this definition, "control" includes the right to grant +patent sublicenses in a manner consistent with the requirements of +this License. + + Each contributor grants you a non-exclusive, worldwide, royalty-free +patent license under the contributor's essential patent claims, to +make, use, sell, offer for sale, import and otherwise run, modify and +propagate the contents of its contributor version. + + In the following three paragraphs, a "patent license" is any express +agreement or commitment, however denominated, not to enforce a patent +(such as an express permission to practice a patent or covenant not to +sue for patent infringement). To "grant" such a patent license to a +party means to make such an agreement or commitment not to enforce a +patent against the party. + + If you convey a covered work, knowingly relying on a patent license, +and the Corresponding Source of the work is not available for anyone +to copy, free of charge and under the terms of this License, through a +publicly available network server or other readily accessible means, +then you must either (1) cause the Corresponding Source to be so +available, or (2) arrange to deprive yourself of the benefit of the +patent license for this particular work, or (3) arrange, in a manner +consistent with the requirements of this License, to extend the patent +license to downstream recipients. "Knowingly relying" means you have +actual knowledge that, but for the patent license, your conveying the +covered work in a country, or your recipient's use of the covered work +in a country, would infringe one or more identifiable patents in that +country that you have reason to believe are valid. + + If, pursuant to or in connection with a single transaction or +arrangement, you convey, or propagate by procuring conveyance of, a +covered work, and grant a patent license to some of the parties +receiving the covered work authorizing them to use, propagate, modify +or convey a specific copy of the covered work, then the patent license +you grant is automatically extended to all recipients of the covered +work and works based on it. + + A patent license is "discriminatory" if it does not include within +the scope of its coverage, prohibits the exercise of, or is +conditioned on the non-exercise of one or more of the rights that are +specifically granted under this License. You may not convey a covered +work if you are a party to an arrangement with a third party that is +in the business of distributing software, under which you make payment +to the third party based on the extent of your activity of conveying +the work, and under which the third party grants, to any of the +parties who would receive the covered work from you, a discriminatory +patent license (a) in connection with copies of the covered work +conveyed by you (or copies made from those copies), or (b) primarily +for and in connection with specific products or compilations that +contain the covered work, unless you entered into that arrangement, +or that patent license was granted, prior to 28 March 2007. + + Nothing in this License shall be construed as excluding or limiting +any implied license or other defenses to infringement that may +otherwise be available to you under applicable patent law. + + 12. No Surrender of Others' Freedom. + + If conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot convey a +covered work so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you may +not convey it at all. For example, if you agree to terms that obligate you +to collect a royalty for further conveying from those to whom you convey +the Program, the only way you could satisfy both those terms and this +License would be to refrain entirely from conveying the Program. + + 13. Use with the GNU Affero General Public License. + + Notwithstanding any other provision of this License, you have +permission to link or combine any covered work with a work licensed +under version 3 of the GNU Affero General Public License into a single +combined work, and to convey the resulting work. The terms of this +License will continue to apply to the part which is the covered work, +but the special requirements of the GNU Affero General Public License, +section 13, concerning interaction through a network will apply to the +combination as such. + + 14. Revised Versions of this License. + + The Free Software Foundation may publish revised and/or new versions of +the GNU General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + + Each version is given a distinguishing version number. If the +Program specifies that a certain numbered version of the GNU General +Public License "or any later version" applies to it, you have the +option of following the terms and conditions either of that numbered +version or of any later version published by the Free Software +Foundation. If the Program does not specify a version number of the +GNU General Public License, you may choose any version ever published +by the Free Software Foundation. + + If the Program specifies that a proxy can decide which future +versions of the GNU General Public License can be used, that proxy's +public statement of acceptance of a version permanently authorizes you +to choose that version for the Program. + + Later license versions may give you additional or different +permissions. However, no additional obligations are imposed on any +author or copyright holder as a result of your choosing to follow a +later version. + + 15. Disclaimer of Warranty. + + THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY +APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT +HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY +OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, +THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM +IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF +ALL NECESSARY SERVICING, REPAIR OR CORRECTION. + + 16. Limitation of Liability. + + IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS +THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY +GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE +USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF +DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD +PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), +EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF +SUCH DAMAGES. + + 17. Interpretation of Sections 15 and 16. + + If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +state the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/Readme.md b/Readme.md new file mode 100644 index 0000000..e3b36cc --- /dev/null +++ b/Readme.md @@ -0,0 +1,123 @@ +### Overview + +[![Build Status](https://travis-ci.org/official-stockfish/Stockfish.svg?branch=master)](https://travis-ci.org/official-stockfish/Stockfish) +[![Build Status](https://ci.appveyor.com/api/projects/status/github/official-stockfish/Stockfish?svg=true)](https://ci.appveyor.com/project/mcostalba/stockfish) + +Stockfish is a free UCI chess engine derived from Glaurung 2.1. It is +not a complete chess program and requires some UCI-compatible GUI +(e.g. XBoard with PolyGlot, eboard, Arena, Sigma Chess, Shredder, Chess +Partner or Fritz) in order to be used comfortably. Read the +documentation for your GUI of choice for information about how to use +Stockfish with it. + +This version of Stockfish supports up to 512 cores. The engine defaults +to one search thread, so it is therefore recommended to inspect the value of +the *Threads* UCI parameter, and to make sure it equals the number of CPU +cores on your computer. + +This version of Stockfish has support for Syzygybases. + + +### Files + +This distribution of Stockfish consists of the following files: + + * Readme.md, the file you are currently reading. + + * Copying.txt, a text file containing the GNU General Public License. + + * src, a subdirectory containing the full source code, including a Makefile + that can be used to compile Stockfish on Unix-like systems. + + +### Syzygybases + +**Configuration** + +Syzygybases are configured using the UCI options "SyzygyPath", +"SyzygyProbeDepth", "Syzygy50MoveRule" and "SyzygyProbeLimit". + +The option "SyzygyPath" should be set to the directory or directories that +contain the .rtbw and .rtbz files. Multiple directories should be +separated by ";" on Windows and by ":" on Unix-based operating systems. +**Do not use spaces around the ";" or ":".** + +Example: `C:\tablebases\wdl345;C:\tablebases\wdl6;D:\tablebases\dtz345;D:\tablebases\dtz6` + +It is recommended to store .rtbw files on an SSD. There is no loss in +storing the .rtbz files on a regular HD. + +Increasing the "SyzygyProbeDepth" option lets the engine probe less +aggressively. Set this option to a higher value if you experience too much +slowdown (in terms of nps) due to TB probing. + +Set the "Syzygy50MoveRule" option to false if you want tablebase positions +that are drawn by the 50-move rule to count as win or loss. This may be useful +for correspondence games (because of tablebase adjudication). + +The "SyzygyProbeLimit" option should normally be left at its default value. + +**What to expect** +If the engine is searching a position that is not in the tablebases (e.g. +a position with 7 pieces), it will access the tablebases during the search. +If the engine reports a very large score (typically 123.xx), this means +that it has found a winning line into a tablebase position. + +If the engine is given a position to search that is in the tablebases, it +will use the tablebases at the beginning of the search to preselect all +good moves, i.e. all moves that preserve the win or preserve the draw while +taking into account the 50-move rule. +It will then perform a search only on those moves. **The engine will not move +immediately**, unless there is only a single good move. **The engine likely +will not report a mate score even if the position is known to be won.** + +It is therefore clear that behaviour is not identical to what one might +be used to with Nalimov tablebases. There are technical reasons for this +difference, the main technical reason being that Nalimov tablebases use the +DTM metric (distance-to-mate), while Syzygybases use a variation of the +DTZ metric (distance-to-zero, zero meaning any move that resets the 50-move +counter). This special metric is one of the reasons that Syzygybases are +more compact than Nalimov tablebases, while still storing all information +needed for optimal play and in addition being able to take into account +the 50-move rule. + + +### Compiling it yourself + +On Unix-like systems, it should be possible to compile Stockfish +directly from the source code with the included Makefile. + +Stockfish has support for 32 or 64-bit CPUs, the hardware POPCNT +instruction, big-endian machines such as Power PC, and other platforms. + +In general it is recommended to run `make help` to see a list of make +targets with corresponding descriptions. When not using the Makefile to +compile (for instance with Microsoft MSVC) you need to manually +set/unset some switches in the compiler command line; see file *types.h* +for a quick reference. + +### Resource For Understanding the Code Base + +* [Chessprogramingwiki](https://chessprogramming.wikispaces.com) has good overall chess engines explanations +(techniques used here are well explained like hash maps etc), it was +also recommended by the [support at stockfish.](http://support.stockfishchess.org/discussions/questions/1132-how-to-understand-stockfish-sources) + +* [Here](https://chessprogramming.wikispaces.com/Stockfish) you can find a set of features and techniques used by stockfish and each of them is explained at the wiki, however, it's a generic way rather than focusing on stockfish's own implementation, but it will still help you. + + +### Terms of use + +Stockfish is free, and distributed under the **GNU General Public License** +(GPL). Essentially, this means that you are free to do almost exactly +what you want with the program, including distributing it among your +friends, making it available for download from your web site, selling +it (either by itself or as part of some bigger software package), or +using it as the starting point for a software project of your own. + +The only real limitation is that whenever you distribute Stockfish in +some way, you must always include the full source code, or a pointer +to where the source code can be found. If you make any changes to the +source code, these changes must also be made available under the GPL. + +For full details, read the copy of the GPL found in the file named +*Copying.txt*. diff --git a/Top CPU Contributors.txt b/Top CPU Contributors.txt new file mode 100644 index 0000000..4c2aa47 --- /dev/null +++ b/Top CPU Contributors.txt @@ -0,0 +1,132 @@ +Contributors with >10,000 CPU hours as of January 23, 2018 +Thank you! + +Username CPU Hours Games played +mibere 518300 41835669 +crunchy 375564 29121434 +cw 371664 28748719 +fastgm 299773 20765374 +JojoM 220590 15299913 +glinscott 204517 13932027 +bking_US 187568 12233168 +ctoks 169342 13475495 +spams 149531 10940322 +Thanar 137015 11714855 +velislav 127305 10047749 +vdbergh 121741 9056874 +malala 117291 8126488 +vdv 117218 8289983 +leszek 114825 8331897 +dsmith 114010 7622414 +CSU_Dynasty 113516 9582758 +sqrt2 112407 8782694 +marrco 111143 8222921 +drabel 108168 9061580 +BrunoBanani 104938 7448565 +Data 94621 8433010 +CoffeeOne 90394 3964243 +BRAVONE 80811 5341681 +psk 77195 6156031 +brabos 70284 5685893 +Fisherman 66650 5572406 +nssy 64587 5369140 +Pking_cda 64499 5704075 +sterni1971 63488 5070004 +mgrabiak 62385 5420812 +tvijlbrief 58957 4154234 +jromang 58854 4704502 +dv8silencer 57421 3961325 +sunu 56620 4609155 +tinker 56039 4204914 +biffhero 55743 4810039 +teddybaer 52982 4740444 +bcross 50548 5071599 +renouve 50318 3544864 +Freja 50296 3805120 +robnjr 47504 4131742 +eva42 46542 4044694 +davar 46538 4030604 +finfish 46244 3481661 +rap 46201 3219490 +ttruscott 45037 3645430 +solarlight 44155 4074841 +TueRens 41372 3891510 +ElbertoOne 41321 3920894 +Antihistamine 39218 2792761 +mhunt 38991 2697512 +bigpen0r 37820 3149955 +homyur 35569 3009637 +VoyagerOne 35137 3302650 +mhoram 34770 2684128 +racerschmacer 33022 3231055 +speedycpu 32043 2531964 +EthanOConnor 31638 2143255 +oryx 29574 2767730 +Pyafue 28885 1986098 +jkiiski 28014 1923255 +Garf 27579 2770144 +slakovv 27017 2031279 +Bobo1239 27000 2488707 +pb00067 26817 2306694 +robal 26337 2316795 +hyperbolic.tom 26248 2200777 +rkl 24898 2236013 +SC 23988 2126825 +nabildanial 23524 1586321 +achambord 23495 1942546 +Sharaf_DG 22975 1790697 +chriswk 22876 1947731 +anst 22568 2013953 +Patrick_G 22435 1682293 +cuistot 22201 1383031 +gri 21901 1820968 +Prcuvu 21182 1890546 +Zirie 21171 1493227 +JanErik 20596 1791991 +Isidor 20560 1730290 +xor12 20535 1819280 +team-oh 20364 1653708 +nesoneg 20264 1493435 +rstoesser 19802 1335177 +grandphish2 19402 1834196 +sg4032 18427 1671742 +dew 18263 1423326 +ianh2105 18133 1668562 +MazeOfGalious 18022 1644593 +ville 17900 1539130 +j3corre 17607 975954 +eudhan 17502 1424648 +iisiraider 17175 1118788 +jundery 17172 1115855 +SFTUser 16635 1363975 +purplefishies 16621 1106850 +DragonLord 16599 1252348 +chris 15274 1575333 +xoto 14900 1486261 +dju 14861 901552 +dex 14647 1228763 +nordlandia 14551 1369718 +ronaldjerum 14361 1210607 +OssumOpossum 14149 1029265 +IgorLeMasson 13844 1228391 +enedene 13762 935618 +ako027ako 13442 1250249 +AdrianSA 13324 924980 +bpfliegel 13318 886523 +ncfish1 13056 932344 +wei 12863 1369596 +jpulman 12776 854815 +horst.prack 12436 1151505 +joster 12424 986622 +cisco2015 12265 1205019 +fatmurphy 12015 901134 +modolief 11228 926456 +Dark_wizzie 11214 1017910 +mschmidt 10973 818594 +eastorwest 10970 1117836 +infinity 10762 746397 +SapphireBrand 10692 1024604 +Thomas A. 10553 736094 +pgontarz 10294 878746 +Andrew Grant 10195 922933 +stocky 10083 718114 diff --git a/appveyor.yml b/appveyor.yml new file mode 100644 index 0000000..c711dd6 --- /dev/null +++ b/appveyor.yml @@ -0,0 +1,71 @@ +version: 1.0.{build} +clone_depth: 50 + +branches: + only: + - master + - appveyor + +# Operating system (build VM template) +os: Visual Studio 2015 + +# Build platform, i.e. x86, x64, AnyCPU. This setting is optional. +platform: + - x86 + - x64 + +# build Configuration, i.e. Debug, Release, etc. +configuration: + - Debug + - Release + +matrix: + # The build fail immediately once one of the job fails + fast_finish: true + +# Scripts that are called at very beginning, before repo cloning +init: + - cmake --version + - msbuild /version + +before_build: + - ps: | + # Get sources + $src = get-childitem -Path *.cpp -Recurse | select -ExpandProperty FullName + $src = $src -join ' ' + $src = $src.Replace("\", "/") + + # Build CMakeLists.txt + $t = 'cmake_minimum_required(VERSION 3.8)', + 'project(Stockfish)', + 'set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/src)', + 'set(source_files', $src, ')', + 'add_executable(stockfish ${source_files})' + + # Write CMakeLists.txt withouth BOM + $MyPath = (Get-Item -Path "." -Verbose).FullName + '\CMakeLists.txt' + $Utf8NoBomEncoding = New-Object System.Text.UTF8Encoding $False + [System.IO.File]::WriteAllLines($MyPath, $t, $Utf8NoBomEncoding) + + # Obtain bench reference from git log + $b = git log HEAD | sls "\b[Bb]ench[ :]+[0-9]{7}" | select -first 1 + $bench = $b -match '\D+(\d+)' | % { $matches[1] } + Write-Host "Reference bench:" $bench + $g = "Visual Studio 14 2015" + If (${env:PLATFORM} -eq 'x64') { $g = $g + ' Win64' } + cmake -G "${g}" . + Write-Host "Generated files for: " $g + +build_script: + - cmake --build . --config %CONFIGURATION% -- /verbosity:minimal + +before_test: + - cd src/%CONFIGURATION% + - ps: | + # Verify bench number + ./stockfish bench 2> out.txt 1> null + $s = (gc "./out.txt" | out-string) + $r = ($s -match 'Nodes searched \D+(\d+)' | % { $matches[1] }) + Write-Host "Engine bench:" $r + Write-Host "Reference bench:" $bench + If ($r -ne $bench) { exit 1 } diff --git a/src/Makefile b/src/Makefile new file mode 100644 index 0000000..72afcc3 --- /dev/null +++ b/src/Makefile @@ -0,0 +1,560 @@ +# Stockfish, a UCI chess playing engine derived from Glaurung 2.1 +# Copyright (C) 2004-2008 Tord Romstad (Glaurung author) +# Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad +# Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad +# +# Stockfish is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# Stockfish is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + + +### ========================================================================== +### Section 1. General Configuration +### ========================================================================== + +### Establish the operating system name +KERNEL = $(shell uname -s) +ifeq ($(KERNEL),Linux) + OS = $(shell uname -o) +endif + +### Executable name +EXE = stockfish + +### Installation dir definitions +PREFIX = /usr/local +BINDIR = $(PREFIX)/bin + +### Built-in benchmark for pgo-builds +PGOBENCH = ./$(EXE) bench + +### Object files +OBJS = benchmark.o bitbase.o bitboard.o endgame.o evaluate.o main.o \ + material.o misc.o movegen.o movepick.o pawns.o position.o psqt.o \ + search.o thread.o timeman.o tt.o uci.o ucioption.o syzygy/tbprobe.o + +### ========================================================================== +### Section 2. High-level Configuration +### ========================================================================== +# +# flag --- Comp switch --- Description +# ---------------------------------------------------------------------------- +# +# debug = yes/no --- -DNDEBUG --- Enable/Disable debug mode +# sanitize = undefined/thread/no (-fsanitize ) +# --- ( undefined ) --- enable undefined behavior checks +# --- ( thread ) --- enable threading error checks +# optimize = yes/no --- (-O3/-fast etc.) --- Enable/Disable optimizations +# arch = (name) --- (-arch) --- Target architecture +# bits = 64/32 --- -DIS_64BIT --- 64-/32-bit operating system +# prefetch = yes/no --- -DUSE_PREFETCH --- Use prefetch asm-instruction +# popcnt = yes/no --- -DUSE_POPCNT --- Use popcnt asm-instruction +# sse = yes/no --- -msse --- Use Intel Streaming SIMD Extensions +# pext = yes/no --- -DUSE_PEXT --- Use pext x86_64 asm-instruction +# +# Note that Makefile is space sensitive, so when adding new architectures +# or modifying existing flags, you have to make sure there are no extra spaces +# at the end of the line for flag values. + +### 2.1. General and architecture defaults +optimize = yes +debug = no +sanitize = no +bits = 32 +prefetch = no +popcnt = no +sse = no +pext = no + +### 2.2 Architecture specific + +ifeq ($(ARCH),general-32) + arch = any +endif + +ifeq ($(ARCH),x86-32-old) + arch = i386 +endif + +ifeq ($(ARCH),x86-32) + arch = i386 + prefetch = yes + sse = yes +endif + +ifeq ($(ARCH),general-64) + arch = any + bits = 64 +endif + +ifeq ($(ARCH),x86-64) + arch = x86_64 + bits = 64 + prefetch = yes + sse = yes +endif + +ifeq ($(ARCH),x86-64-modern) + arch = x86_64 + bits = 64 + prefetch = yes + popcnt = yes + sse = yes +endif + +ifeq ($(ARCH),x86-64-bmi2) + arch = x86_64 + bits = 64 + prefetch = yes + popcnt = yes + sse = yes + pext = yes +endif + +ifeq ($(ARCH),armv7) + arch = armv7 + prefetch = yes +endif + +ifeq ($(ARCH),ppc-32) + arch = ppc +endif + +ifeq ($(ARCH),ppc-64) + arch = ppc64 + bits = 64 +endif + + +### ========================================================================== +### Section 3. Low-level configuration +### ========================================================================== + +### 3.1 Selecting compiler (default = gcc) + +CXXFLAGS += -Wall -Wcast-qual -fno-exceptions -std=c++11 $(EXTRACXXFLAGS) +DEPENDFLAGS += -std=c++11 +LDFLAGS += $(EXTRALDFLAGS) + +ifeq ($(COMP),) + COMP=gcc +endif + +ifeq ($(COMP),gcc) + comp=gcc + CXX=g++ + CXXFLAGS += -pedantic -Wextra -Wshadow + + ifeq ($(ARCH),armv7) + ifeq ($(OS),Android) + CXXFLAGS += -m$(bits) + LDFLAGS += -m$(bits) + endif + else + CXXFLAGS += -m$(bits) + LDFLAGS += -m$(bits) + endif + + ifneq ($(KERNEL),Darwin) + LDFLAGS += -Wl,--no-as-needed + endif +endif + +ifeq ($(COMP),mingw) + comp=mingw + + ifeq ($(KERNEL),Linux) + ifeq ($(bits),64) + ifeq ($(shell which x86_64-w64-mingw32-c++-posix),) + CXX=x86_64-w64-mingw32-c++ + else + CXX=x86_64-w64-mingw32-c++-posix + endif + else + ifeq ($(shell which i686-w64-mingw32-c++-posix),) + CXX=i686-w64-mingw32-c++ + else + CXX=i686-w64-mingw32-c++-posix + endif + endif + else + CXX=g++ + endif + + CXXFLAGS += -Wextra -Wshadow + LDFLAGS += -static +endif + +ifeq ($(COMP),icc) + comp=icc + CXX=icpc + CXXFLAGS += -diag-disable 1476,10120 -Wcheck -Wabi -Wdeprecated -strict-ansi +endif + +ifeq ($(COMP),clang) + comp=clang + CXX=clang++ + CXXFLAGS += -pedantic -Wextra -Wshadow +ifneq ($(KERNEL),Darwin) +ifneq ($(KERNEL),OpenBSD) + LDFLAGS += -latomic +endif +endif + + ifeq ($(ARCH),armv7) + ifeq ($(OS),Android) + CXXFLAGS += -m$(bits) + LDFLAGS += -m$(bits) + endif + else + CXXFLAGS += -m$(bits) + LDFLAGS += -m$(bits) + endif +endif + +ifeq ($(comp),icc) + profile_make = icc-profile-make + profile_use = icc-profile-use +else +ifeq ($(comp),clang) + profile_make = clang-profile-make + profile_use = clang-profile-use +else + profile_make = gcc-profile-make + profile_use = gcc-profile-use +endif +endif + +ifeq ($(KERNEL),Darwin) + CXXFLAGS += -arch $(arch) -mmacosx-version-min=10.9 + LDFLAGS += -arch $(arch) -mmacosx-version-min=10.9 +endif + +### Travis CI script uses COMPILER to overwrite CXX +ifdef COMPILER + COMPCXX=$(COMPILER) +endif + +### Allow overwriting CXX from command line +ifdef COMPCXX + CXX=$(COMPCXX) +endif + +### On mingw use Windows threads, otherwise POSIX +ifneq ($(comp),mingw) + # On Android Bionic's C library comes with its own pthread implementation bundled in + ifneq ($(OS),Android) + # Haiku has pthreads in its libroot, so only link it in on other platforms + ifneq ($(KERNEL),Haiku) + LDFLAGS += -lpthread + endif + endif +endif + +### 3.2.1 Debugging +ifeq ($(debug),no) + CXXFLAGS += -DNDEBUG +else + CXXFLAGS += -g +endif + +### 3.2.2 Debugging with undefined behavior sanitizers +ifneq ($(sanitize),no) + CXXFLAGS += -g3 -fsanitize=$(sanitize) -fuse-ld=gold + LDFLAGS += -fsanitize=$(sanitize) -fuse-ld=gold +endif + +### 3.3 Optimization +ifeq ($(optimize),yes) + + CXXFLAGS += -O3 + + ifeq ($(comp),gcc) + + ifeq ($(KERNEL),Darwin) + ifeq ($(arch),i386) + CXXFLAGS += -mdynamic-no-pic + endif + ifeq ($(arch),x86_64) + CXXFLAGS += -mdynamic-no-pic + endif + endif + + ifeq ($(OS), Android) + CXXFLAGS += -fno-gcse -mthumb -march=armv7-a -mfloat-abi=softfp + endif + endif + + ifeq ($(comp),icc) + ifeq ($(KERNEL),Darwin) + CXXFLAGS += -mdynamic-no-pic + endif + endif + + ifeq ($(comp),clang) + ifeq ($(KERNEL),Darwin) + CXXFLAGS += -flto + LDFLAGS += $(CXXFLAGS) + ifeq ($(arch),i386) + CXXFLAGS += -mdynamic-no-pic + endif + ifeq ($(arch),x86_64) + CXXFLAGS += -mdynamic-no-pic + endif + endif + endif +endif + +### 3.4 Bits +ifeq ($(bits),64) + CXXFLAGS += -DIS_64BIT +endif + +### 3.5 prefetch +ifeq ($(prefetch),yes) + ifeq ($(sse),yes) + CXXFLAGS += -msse + DEPENDFLAGS += -msse + endif +else + CXXFLAGS += -DNO_PREFETCH +endif + +### 3.6 popcnt +ifeq ($(popcnt),yes) + ifeq ($(comp),icc) + CXXFLAGS += -msse3 -DUSE_POPCNT + else + CXXFLAGS += -msse3 -mpopcnt -DUSE_POPCNT + endif +endif + +### 3.7 pext +ifeq ($(pext),yes) + CXXFLAGS += -DUSE_PEXT + ifeq ($(comp),$(filter $(comp),gcc clang mingw)) + CXXFLAGS += -mbmi2 + endif +endif + +### 3.8 Link Time Optimization, it works since gcc 4.5 but not on mingw under Windows. +### This is a mix of compile and link time options because the lto link phase +### needs access to the optimization flags. +ifeq ($(comp),gcc) + ifeq ($(optimize),yes) + ifeq ($(debug),no) + CXXFLAGS += -flto + LDFLAGS += $(CXXFLAGS) + endif + endif +endif + +ifeq ($(comp),mingw) + ifeq ($(KERNEL),Linux) + ifeq ($(optimize),yes) + ifeq ($(debug),no) + CXXFLAGS += -flto + LDFLAGS += $(CXXFLAGS) + endif + endif + endif +endif + +### 3.9 Android 5 can only run position independent executables. Note that this +### breaks Android 4.0 and earlier. +ifeq ($(OS), Android) + CXXFLAGS += -fPIE + LDFLAGS += -fPIE -pie +endif + + +### ========================================================================== +### Section 4. Public targets +### ========================================================================== + +help: + @echo "" + @echo "To compile stockfish, type: " + @echo "" + @echo "make target ARCH=arch [COMP=compiler] [COMPCXX=cxx]" + @echo "" + @echo "Supported targets:" + @echo "" + @echo "build > Standard build" + @echo "profile-build > PGO build" + @echo "strip > Strip executable" + @echo "install > Install executable" + @echo "clean > Clean up" + @echo "" + @echo "Supported archs:" + @echo "" + @echo "x86-64 > x86 64-bit" + @echo "x86-64-modern > x86 64-bit with popcnt support" + @echo "x86-64-bmi2 > x86 64-bit with pext support" + @echo "x86-32 > x86 32-bit with SSE support" + @echo "x86-32-old > x86 32-bit fall back for old hardware" + @echo "ppc-64 > PPC 64-bit" + @echo "ppc-32 > PPC 32-bit" + @echo "armv7 > ARMv7 32-bit" + @echo "general-64 > unspecified 64-bit" + @echo "general-32 > unspecified 32-bit" + @echo "" + @echo "Supported compilers:" + @echo "" + @echo "gcc > Gnu compiler (default)" + @echo "mingw > Gnu compiler with MinGW under Windows" + @echo "clang > LLVM Clang compiler" + @echo "icc > Intel compiler" + @echo "" + @echo "Simple examples. If you don't know what to do, you likely want to run: " + @echo "" + @echo "make build ARCH=x86-64 (This is for 64-bit systems)" + @echo "make build ARCH=x86-32 (This is for 32-bit systems)" + @echo "" + @echo "Advanced examples, for experienced users: " + @echo "" + @echo "make build ARCH=x86-64 COMP=clang" + @echo "make profile-build ARCH=x86-64-modern COMP=gcc COMPCXX=g++-4.8" + @echo "" + + +.PHONY: help build profile-build strip install clean objclean profileclean help \ + config-sanity icc-profile-use icc-profile-make gcc-profile-use gcc-profile-make \ + clang-profile-use clang-profile-make + +build: config-sanity + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) all + +profile-build: config-sanity objclean profileclean + @echo "" + @echo "Step 1/4. Building instrumented executable ..." + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) $(profile_make) + @echo "" + @echo "Step 2/4. Running benchmark for pgo-build ..." + $(PGOBENCH) > /dev/null + @echo "" + @echo "Step 3/4. Building optimized executable ..." + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) objclean + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) $(profile_use) + @echo "" + @echo "Step 4/4. Deleting profile data ..." + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) profileclean + +strip: + strip $(EXE) + +install: + -mkdir -p -m 755 $(BINDIR) + -cp $(EXE) $(BINDIR) + -strip $(BINDIR)/$(EXE) + +#clean all +clean: objclean profileclean + @rm -f .depend *~ core + +# clean binaries and objects +objclean: + @rm -f $(EXE) $(EXE).exe *.o ./syzygy/*.o + +# clean auxiliary profiling files +profileclean: + @rm -rf profdir + @rm -f bench.txt *.gcda ./syzygy/*.gcda *.gcno ./syzygy/*.gcno + @rm -f stockfish.profdata *.profraw + +default: + help + +### ========================================================================== +### Section 5. Private targets +### ========================================================================== + +all: $(EXE) .depend + +config-sanity: + @echo "" + @echo "Config:" + @echo "debug: '$(debug)'" + @echo "sanitize: '$(sanitize)'" + @echo "optimize: '$(optimize)'" + @echo "arch: '$(arch)'" + @echo "bits: '$(bits)'" + @echo "kernel: '$(KERNEL)'" + @echo "os: '$(OS)'" + @echo "prefetch: '$(prefetch)'" + @echo "popcnt: '$(popcnt)'" + @echo "sse: '$(sse)'" + @echo "pext: '$(pext)'" + @echo "" + @echo "Flags:" + @echo "CXX: $(CXX)" + @echo "CXXFLAGS: $(CXXFLAGS)" + @echo "LDFLAGS: $(LDFLAGS)" + @echo "" + @echo "Testing config sanity. If this fails, try 'make help' ..." + @echo "" + @test "$(debug)" = "yes" || test "$(debug)" = "no" + @test "$(sanitize)" = "undefined" || test "$(sanitize)" = "thread" || test "$(sanitize)" = "no" + @test "$(optimize)" = "yes" || test "$(optimize)" = "no" + @test "$(arch)" = "any" || test "$(arch)" = "x86_64" || test "$(arch)" = "i386" || \ + test "$(arch)" = "ppc64" || test "$(arch)" = "ppc" || test "$(arch)" = "armv7" + @test "$(bits)" = "32" || test "$(bits)" = "64" + @test "$(prefetch)" = "yes" || test "$(prefetch)" = "no" + @test "$(popcnt)" = "yes" || test "$(popcnt)" = "no" + @test "$(sse)" = "yes" || test "$(sse)" = "no" + @test "$(pext)" = "yes" || test "$(pext)" = "no" + @test "$(comp)" = "gcc" || test "$(comp)" = "icc" || test "$(comp)" = "mingw" || test "$(comp)" = "clang" + +$(EXE): $(OBJS) + $(CXX) -o $@ $(OBJS) $(LDFLAGS) + +clang-profile-make: + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) \ + EXTRACXXFLAGS='-fprofile-instr-generate ' \ + EXTRALDFLAGS=' -fprofile-instr-generate' \ + all + +clang-profile-use: + llvm-profdata merge -output=stockfish.profdata *.profraw + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) \ + EXTRACXXFLAGS='-fprofile-instr-use=stockfish.profdata' \ + EXTRALDFLAGS='-fprofile-use ' \ + all + +gcc-profile-make: + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) \ + EXTRACXXFLAGS='-fprofile-generate' \ + EXTRALDFLAGS='-lgcov' \ + all + +gcc-profile-use: + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) \ + EXTRACXXFLAGS='-fprofile-use -fno-peel-loops -fno-tracer' \ + EXTRALDFLAGS='-lgcov' \ + all + +icc-profile-make: + @mkdir -p profdir + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) \ + EXTRACXXFLAGS='-prof-gen=srcpos -prof_dir ./profdir' \ + all + +icc-profile-use: + $(MAKE) ARCH=$(ARCH) COMP=$(COMP) \ + EXTRACXXFLAGS='-prof_use -prof_dir ./profdir' \ + all + +.depend: + -@$(CXX) $(DEPENDFLAGS) -MM $(OBJS:.o=.cpp) > $@ 2> /dev/null + +-include .depend + diff --git a/src/benchmark.cpp b/src/benchmark.cpp new file mode 100644 index 0000000..1c69dca --- /dev/null +++ b/src/benchmark.cpp @@ -0,0 +1,156 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include +#include + +#include "position.h" + +using namespace std; + +namespace { + +const vector Defaults = { + "setoption name UCI_Chess960 value false", + "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 10", + "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 11", + "4rrk1/pp1n3p/3q2pQ/2p1pb2/2PP4/2P3N1/P2B2PP/4RRK1 b - - 7 19", + "rq3rk1/ppp2ppp/1bnpb3/3N2B1/3NP3/7P/PPPQ1PP1/2KR3R w - - 7 14 moves d4e6", + "r1bq1r1k/1pp1n1pp/1p1p4/4p2Q/4Pp2/1BNP4/PPP2PPP/3R1RK1 w - - 2 14 moves g2g4", + "r3r1k1/2p2ppp/p1p1bn2/8/1q2P3/2NPQN2/PPP3PP/R4RK1 b - - 2 15", + "r1bbk1nr/pp3p1p/2n5/1N4p1/2Np1B2/8/PPP2PPP/2KR1B1R w kq - 0 13", + "r1bq1rk1/ppp1nppp/4n3/3p3Q/3P4/1BP1B3/PP1N2PP/R4RK1 w - - 1 16", + "4r1k1/r1q2ppp/ppp2n2/4P3/5Rb1/1N1BQ3/PPP3PP/R5K1 w - - 1 17", + "2rqkb1r/ppp2p2/2npb1p1/1N1Nn2p/2P1PP2/8/PP2B1PP/R1BQK2R b KQ - 0 11", + "r1bq1r1k/b1p1npp1/p2p3p/1p6/3PP3/1B2NN2/PP3PPP/R2Q1RK1 w - - 1 16", + "3r1rk1/p5pp/bpp1pp2/8/q1PP1P2/b3P3/P2NQRPP/1R2B1K1 b - - 6 22", + "r1q2rk1/2p1bppp/2Pp4/p6b/Q1PNp3/4B3/PP1R1PPP/2K4R w - - 2 18", + "4k2r/1pb2ppp/1p2p3/1R1p4/3P4/2r1PN2/P4PPP/1R4K1 b - - 3 22", + "3q2k1/pb3p1p/4pbp1/2r5/PpN2N2/1P2P2P/5PP1/Q2R2K1 b - - 4 26", + "6k1/6p1/6Pp/ppp5/3pn2P/1P3K2/1PP2P2/3N4 b - - 0 1", + "3b4/5kp1/1p1p1p1p/pP1PpP1P/P1P1P3/3KN3/8/8 w - - 0 1", + "2K5/p7/7P/5pR1/8/5k2/r7/8 w - - 0 1 moves g5g6 f3e3 g6g5 e3f3", + "8/6pk/1p6/8/PP3p1p/5P2/4KP1q/3Q4 w - - 0 1", + "7k/3p2pp/4q3/8/4Q3/5Kp1/P6b/8 w - - 0 1", + "8/2p5/8/2kPKp1p/2p4P/2P5/3P4/8 w - - 0 1", + "8/1p3pp1/7p/5P1P/2k3P1/8/2K2P2/8 w - - 0 1", + "8/pp2r1k1/2p1p3/3pP2p/1P1P1P1P/P5KR/8/8 w - - 0 1", + "8/3p4/p1bk3p/Pp6/1Kp1PpPp/2P2P1P/2P5/5B2 b - - 0 1", + "5k2/7R/4P2p/5K2/p1r2P1p/8/8/8 b - - 0 1", + "6k1/6p1/P6p/r1N5/5p2/7P/1b3PP1/4R1K1 w - - 0 1", + "1r3k2/4q3/2Pp3b/3Bp3/2Q2p2/1p1P2P1/1P2KP2/3N4 w - - 0 1", + "6k1/4pp1p/3p2p1/P1pPb3/R7/1r2P1PP/3B1P2/6K1 w - - 0 1", + "8/3p3B/5p2/5P2/p7/PP5b/k7/6K1 w - - 0 1", + + // 5-man positions + "8/8/8/8/5kp1/P7/8/1K1N4 w - - 0 1", // Kc2 - mate + "8/8/8/5N2/8/p7/8/2NK3k w - - 0 1", // Na2 - mate + "8/3k4/8/8/8/4B3/4KB2/2B5 w - - 0 1", // draw + + // 6-man positions + "8/8/1P6/5pr1/8/4R3/7k/2K5 w - - 0 1", // Re5 - mate + "8/2p4P/8/kr6/6R1/8/8/1K6 w - - 0 1", // Ka2 - mate + "8/8/3P3k/8/1p6/8/1P6/1K3n2 b - - 0 1", // Nd2 - draw + + // 7-man positions + "8/R7/2q5/8/6k1/8/1P5p/K6R w - - 0 124", // Draw + + // Mate and stalemate positions + "6k1/3b3r/1p1p4/p1n2p2/1PPNpP1q/P3Q1p1/1R1RB1P1/5K2 b - - 0 1", + "r2r1n2/pp2bk2/2p1p2p/3q4/3PN1QP/2P3R1/P4PP1/5RK1 w - - 0 1", + "8/8/8/8/8/6k1/6p1/6K1 w - -", + "7k/7P/6K1/8/3B4/8/8/8 b - -", + + // Chess 960 + "setoption name UCI_Chess960 value true", + "bbqnnrkr/pppppppp/8/8/8/8/PPPPPPPP/BBQNNRKR w KQkq - 0 1 moves g2g3 d7d5 d2d4 c8h3 c1g5 e8d6 g5e7 f7f6", + "setoption name UCI_Chess960 value false" +}; + +} // namespace + +/// setup_bench() builds a list of UCI commands to be run by bench. There +/// are five parameters: TT size in MB, number of search threads that +/// should be used, the limit value spent for each position, a file name +/// where to look for positions in FEN format and the type of the limit: +/// depth, perft, nodes and movetime (in millisecs). +/// +/// bench -> search default positions up to depth 13 +/// bench 64 1 15 -> search default positions up to depth 15 (TT = 64MB) +/// bench 64 4 5000 current movetime -> search current position with 4 threads for 5 sec +/// bench 64 1 100000 default nodes -> search default positions for 100K nodes each +/// bench 16 1 5 default perft -> run a perft 5 on default positions + +vector setup_bench(const Position& current, istream& is) { + + vector fens, list; + string go, token; + + // Assign default values to missing arguments + string ttSize = (is >> token) ? token : "16"; + string threads = (is >> token) ? token : "1"; + string limit = (is >> token) ? token : "13"; + string fenFile = (is >> token) ? token : "default"; + string limitType = (is >> token) ? token : "depth"; + + go = "go " + limitType + " " + limit; + + if (fenFile == "default") + fens = Defaults; + + else if (fenFile == "current") + fens.push_back(current.fen()); + + else + { + string fen; + ifstream file(fenFile); + + if (!file.is_open()) + { + cerr << "Unable to open file " << fenFile << endl; + exit(EXIT_FAILURE); + } + + while (getline(file, fen)) + if (!fen.empty()) + fens.push_back(fen); + + file.close(); + } + + list.emplace_back("ucinewgame"); + list.emplace_back("setoption name Threads value " + threads); + list.emplace_back("setoption name Hash value " + ttSize); + + for (const string& fen : fens) + if (fen.find("setoption") != string::npos) + list.emplace_back(fen); + else + { + list.emplace_back("position fen " + fen); + list.emplace_back(go); + } + + return list; +} diff --git a/src/bitbase.cpp b/src/bitbase.cpp new file mode 100644 index 0000000..3c9bf6e --- /dev/null +++ b/src/bitbase.cpp @@ -0,0 +1,180 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include +#include + +#include "bitboard.h" +#include "types.h" + +namespace { + + // There are 24 possible pawn squares: the first 4 files and ranks from 2 to 7 + const unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608 + + // Each uint32_t stores results of 32 positions, one per bit + uint32_t KPKBitbase[MAX_INDEX / 32]; + + // A KPK bitbase index is an integer in [0, IndexMax] range + // + // Information is mapped in a way that minimizes the number of iterations: + // + // bit 0- 5: white king square (from SQ_A1 to SQ_H8) + // bit 6-11: black king square (from SQ_A1 to SQ_H8) + // bit 12: side to move (WHITE or BLACK) + // bit 13-14: white pawn file (from FILE_A to FILE_D) + // bit 15-17: white pawn RANK_7 - rank (from RANK_7 - RANK_7 to RANK_7 - RANK_2) + unsigned index(Color us, Square bksq, Square wksq, Square psq) { + return wksq | (bksq << 6) | (us << 12) | (file_of(psq) << 13) | ((RANK_7 - rank_of(psq)) << 15); + } + + enum Result { + INVALID = 0, + UNKNOWN = 1, + DRAW = 2, + WIN = 4 + }; + + Result& operator|=(Result& r, Result v) { return r = Result(r | v); } + + struct KPKPosition { + KPKPosition() = default; + explicit KPKPosition(unsigned idx); + operator Result() const { return result; } + Result classify(const std::vector& db) + { return us == WHITE ? classify(db) : classify(db); } + + template Result classify(const std::vector& db); + + Color us; + Square ksq[COLOR_NB], psq; + Result result; + }; + +} // namespace + + +bool Bitbases::probe(Square wksq, Square wpsq, Square bksq, Color us) { + + assert(file_of(wpsq) <= FILE_D); + + unsigned idx = index(us, bksq, wksq, wpsq); + return KPKBitbase[idx / 32] & (1 << (idx & 0x1F)); +} + + +void Bitbases::init() { + + std::vector db(MAX_INDEX); + unsigned idx, repeat = 1; + + // Initialize db with known win / draw positions + for (idx = 0; idx < MAX_INDEX; ++idx) + db[idx] = KPKPosition(idx); + + // Iterate through the positions until none of the unknown positions can be + // changed to either wins or draws (15 cycles needed). + while (repeat) + for (repeat = idx = 0; idx < MAX_INDEX; ++idx) + repeat |= (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN); + + // Map 32 results into one KPKBitbase[] entry + for (idx = 0; idx < MAX_INDEX; ++idx) + if (db[idx] == WIN) + KPKBitbase[idx / 32] |= 1 << (idx & 0x1F); +} + + +namespace { + + KPKPosition::KPKPosition(unsigned idx) { + + ksq[WHITE] = Square((idx >> 0) & 0x3F); + ksq[BLACK] = Square((idx >> 6) & 0x3F); + us = Color ((idx >> 12) & 0x01); + psq = make_square(File((idx >> 13) & 0x3), Rank(RANK_7 - ((idx >> 15) & 0x7))); + + // Check if two pieces are on the same square or if a king can be captured + if ( distance(ksq[WHITE], ksq[BLACK]) <= 1 + || ksq[WHITE] == psq + || ksq[BLACK] == psq + || (us == WHITE && (PawnAttacks[WHITE][psq] & ksq[BLACK]))) + result = INVALID; + + // Immediate win if a pawn can be promoted without getting captured + else if ( us == WHITE + && rank_of(psq) == RANK_7 + && ksq[us] != psq + NORTH + && ( distance(ksq[~us], psq + NORTH) > 1 + || (PseudoAttacks[KING][ksq[us]] & (psq + NORTH)))) + result = WIN; + + // Immediate draw if it is a stalemate or a king captures undefended pawn + else if ( us == BLACK + && ( !(PseudoAttacks[KING][ksq[us]] & ~(PseudoAttacks[KING][ksq[~us]] | PawnAttacks[~us][psq])) + || (PseudoAttacks[KING][ksq[us]] & psq & ~PseudoAttacks[KING][ksq[~us]]))) + result = DRAW; + + // Position will be classified later + else + result = UNKNOWN; + } + + template + Result KPKPosition::classify(const std::vector& db) { + + // White to move: If one move leads to a position classified as WIN, the result + // of the current position is WIN. If all moves lead to positions classified + // as DRAW, the current position is classified as DRAW, otherwise the current + // position is classified as UNKNOWN. + // + // Black to move: If one move leads to a position classified as DRAW, the result + // of the current position is DRAW. If all moves lead to positions classified + // as WIN, the position is classified as WIN, otherwise the current position is + // classified as UNKNOWN. + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Result Good = (Us == WHITE ? WIN : DRAW); + const Result Bad = (Us == WHITE ? DRAW : WIN); + + Result r = INVALID; + Bitboard b = PseudoAttacks[KING][ksq[Us]]; + + while (b) + r |= Us == WHITE ? db[index(Them, ksq[Them] , pop_lsb(&b), psq)] + : db[index(Them, pop_lsb(&b), ksq[Them] , psq)]; + + if (Us == WHITE) + { + if (rank_of(psq) < RANK_7) // Single push + r |= db[index(Them, ksq[Them], ksq[Us], psq + NORTH)]; + + if ( rank_of(psq) == RANK_2 // Double push + && psq + NORTH != ksq[Us] + && psq + NORTH != ksq[Them]) + r |= db[index(Them, ksq[Them], ksq[Us], psq + NORTH + NORTH)]; + } + + return result = r & Good ? Good : r & UNKNOWN ? UNKNOWN : Bad; + } + +} // namespace diff --git a/src/bitboard.cpp b/src/bitboard.cpp new file mode 100644 index 0000000..ba00c78 --- /dev/null +++ b/src/bitboard.cpp @@ -0,0 +1,326 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include + +#include "bitboard.h" +#include "misc.h" + +uint8_t PopCnt16[1 << 16]; +int SquareDistance[SQUARE_NB][SQUARE_NB]; + +Bitboard SquareBB[SQUARE_NB]; +Bitboard FileBB[FILE_NB]; +Bitboard RankBB[RANK_NB]; +Bitboard AdjacentFilesBB[FILE_NB]; +Bitboard ForwardRanksBB[COLOR_NB][RANK_NB]; +Bitboard BetweenBB[SQUARE_NB][SQUARE_NB]; +Bitboard LineBB[SQUARE_NB][SQUARE_NB]; +Bitboard DistanceRingBB[SQUARE_NB][8]; +Bitboard ForwardFileBB[COLOR_NB][SQUARE_NB]; +Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB]; +Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB]; +Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; +Bitboard PawnAttacks[COLOR_NB][SQUARE_NB]; + +Magic RookMagics[SQUARE_NB]; +Magic BishopMagics[SQUARE_NB]; + +namespace { + + // De Bruijn sequences. See chessprogramming.wikispaces.com/BitScan + const uint64_t DeBruijn64 = 0x3F79D71B4CB0A89ULL; + const uint32_t DeBruijn32 = 0x783A9B23; + + int MSBTable[256]; // To implement software msb() + Square BSFTable[SQUARE_NB]; // To implement software bitscan + Bitboard RookTable[0x19000]; // To store rook attacks + Bitboard BishopTable[0x1480]; // To store bishop attacks + + void init_magics(Bitboard table[], Magic magics[], Direction directions[]); + + // bsf_index() returns the index into BSFTable[] to look up the bitscan. Uses + // Matt Taylor's folding for 32 bit case, extended to 64 bit by Kim Walisch. + + unsigned bsf_index(Bitboard b) { + b ^= b - 1; + return Is64Bit ? (b * DeBruijn64) >> 58 + : ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn32) >> 26; + } + + + // popcount16() counts the non-zero bits using SWAR-Popcount algorithm + + unsigned popcount16(unsigned u) { + u -= (u >> 1) & 0x5555U; + u = ((u >> 2) & 0x3333U) + (u & 0x3333U); + u = ((u >> 4) + u) & 0x0F0FU; + return (u * 0x0101U) >> 8; + } +} + +#ifdef NO_BSF + +/// Software fall-back of lsb() and msb() for CPU lacking hardware support + +Square lsb(Bitboard b) { + assert(b); + return BSFTable[bsf_index(b)]; +} + +Square msb(Bitboard b) { + + assert(b); + unsigned b32; + int result = 0; + + if (b > 0xFFFFFFFF) + { + b >>= 32; + result = 32; + } + + b32 = unsigned(b); + + if (b32 > 0xFFFF) + { + b32 >>= 16; + result += 16; + } + + if (b32 > 0xFF) + { + b32 >>= 8; + result += 8; + } + + return Square(result + MSBTable[b32]); +} + +#endif // ifdef NO_BSF + + +/// Bitboards::pretty() returns an ASCII representation of a bitboard suitable +/// to be printed to standard output. Useful for debugging. + +const std::string Bitboards::pretty(Bitboard b) { + + std::string s = "+---+---+---+---+---+---+---+---+\n"; + + for (Rank r = RANK_8; r >= RANK_1; --r) + { + for (File f = FILE_A; f <= FILE_H; ++f) + s += b & make_square(f, r) ? "| X " : "| "; + + s += "|\n+---+---+---+---+---+---+---+---+\n"; + } + + return s; +} + + +/// Bitboards::init() initializes various bitboard tables. It is called at +/// startup and relies on global objects to be already zero-initialized. + +void Bitboards::init() { + + for (unsigned i = 0; i < (1 << 16); ++i) + PopCnt16[i] = (uint8_t) popcount16(i); + + for (Square s = SQ_A1; s <= SQ_H8; ++s) + { + SquareBB[s] = 1ULL << s; + BSFTable[bsf_index(SquareBB[s])] = s; + } + + for (Bitboard b = 2; b < 256; ++b) + MSBTable[b] = MSBTable[b - 1] + !more_than_one(b); + + for (File f = FILE_A; f <= FILE_H; ++f) + FileBB[f] = f > FILE_A ? FileBB[f - 1] << 1 : FileABB; + + for (Rank r = RANK_1; r <= RANK_8; ++r) + RankBB[r] = r > RANK_1 ? RankBB[r - 1] << 8 : Rank1BB; + + for (File f = FILE_A; f <= FILE_H; ++f) + AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0); + + for (Rank r = RANK_1; r < RANK_8; ++r) + ForwardRanksBB[WHITE][r] = ~(ForwardRanksBB[BLACK][r + 1] = ForwardRanksBB[BLACK][r] | RankBB[r]); + + for (Color c = WHITE; c <= BLACK; ++c) + for (Square s = SQ_A1; s <= SQ_H8; ++s) + { + ForwardFileBB [c][s] = ForwardRanksBB[c][rank_of(s)] & FileBB[file_of(s)]; + PawnAttackSpan[c][s] = ForwardRanksBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)]; + PassedPawnMask[c][s] = ForwardFileBB [c][s] | PawnAttackSpan[c][s]; + } + + for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1) + for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2) + if (s1 != s2) + { + SquareDistance[s1][s2] = std::max(distance(s1, s2), distance(s1, s2)); + DistanceRingBB[s1][SquareDistance[s1][s2] - 1] |= s2; + } + + int steps[][5] = { {}, { 7, 9 }, { 6, 10, 15, 17 }, {}, {}, {}, { 1, 7, 8, 9 } }; + + for (Color c = WHITE; c <= BLACK; ++c) + for (PieceType pt : { PAWN, KNIGHT, KING }) + for (Square s = SQ_A1; s <= SQ_H8; ++s) + for (int i = 0; steps[pt][i]; ++i) + { + Square to = s + Direction(c == WHITE ? steps[pt][i] : -steps[pt][i]); + + if (is_ok(to) && distance(s, to) < 3) + { + if (pt == PAWN) + PawnAttacks[c][s] |= to; + else + PseudoAttacks[pt][s] |= to; + } + } + + Direction RookDirections[] = { NORTH, EAST, SOUTH, WEST }; + Direction BishopDirections[] = { NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST }; + + init_magics(RookTable, RookMagics, RookDirections); + init_magics(BishopTable, BishopMagics, BishopDirections); + + for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1) + { + PseudoAttacks[QUEEN][s1] = PseudoAttacks[BISHOP][s1] = attacks_bb(s1, 0); + PseudoAttacks[QUEEN][s1] |= PseudoAttacks[ ROOK][s1] = attacks_bb< ROOK>(s1, 0); + + for (PieceType pt : { BISHOP, ROOK }) + for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2) + { + if (!(PseudoAttacks[pt][s1] & s2)) + continue; + + LineBB[s1][s2] = (attacks_bb(pt, s1, 0) & attacks_bb(pt, s2, 0)) | s1 | s2; + BetweenBB[s1][s2] = attacks_bb(pt, s1, SquareBB[s2]) & attacks_bb(pt, s2, SquareBB[s1]); + } + } +} + + +namespace { + + Bitboard sliding_attack(Direction directions[], Square sq, Bitboard occupied) { + + Bitboard attack = 0; + + for (int i = 0; i < 4; ++i) + for (Square s = sq + directions[i]; + is_ok(s) && distance(s, s - directions[i]) == 1; + s += directions[i]) + { + attack |= s; + + if (occupied & s) + break; + } + + return attack; + } + + + // init_magics() computes all rook and bishop attacks at startup. Magic + // bitboards are used to look up attacks of sliding pieces. As a reference see + // chessprogramming.wikispaces.com/Magic+Bitboards. In particular, here we + // use the so called "fancy" approach. + + void init_magics(Bitboard table[], Magic magics[], Direction directions[]) { + + // Optimal PRNG seeds to pick the correct magics in the shortest time + int seeds[][RANK_NB] = { { 8977, 44560, 54343, 38998, 5731, 95205, 104912, 17020 }, + { 728, 10316, 55013, 32803, 12281, 15100, 16645, 255 } }; + + Bitboard occupancy[4096], reference[4096], edges, b; + int epoch[4096] = {}, cnt = 0, size = 0; + + for (Square s = SQ_A1; s <= SQ_H8; ++s) + { + // Board edges are not considered in the relevant occupancies + edges = ((Rank1BB | Rank8BB) & ~rank_bb(s)) | ((FileABB | FileHBB) & ~file_bb(s)); + + // Given a square 's', the mask is the bitboard of sliding attacks from + // 's' computed on an empty board. The index must be big enough to contain + // all the attacks for each possible subset of the mask and so is 2 power + // the number of 1s of the mask. Hence we deduce the size of the shift to + // apply to the 64 or 32 bits word to get the index. + Magic& m = magics[s]; + m.mask = sliding_attack(directions, s, 0) & ~edges; + m.shift = (Is64Bit ? 64 : 32) - popcount(m.mask); + + // Set the offset for the attacks table of the square. We have individual + // table sizes for each square with "Fancy Magic Bitboards". + m.attacks = s == SQ_A1 ? table : magics[s - 1].attacks + size; + + // Use Carry-Rippler trick to enumerate all subsets of masks[s] and + // store the corresponding sliding attack bitboard in reference[]. + b = size = 0; + do { + occupancy[size] = b; + reference[size] = sliding_attack(directions, s, b); + + if (HasPext) + m.attacks[pext(b, m.mask)] = reference[size]; + + size++; + b = (b - m.mask) & m.mask; + } while (b); + + if (HasPext) + continue; + + PRNG rng(seeds[Is64Bit][rank_of(s)]); + + // Find a magic for square 's' picking up an (almost) random number + // until we find the one that passes the verification test. + for (int i = 0; i < size; ) + { + for (m.magic = 0; popcount((m.magic * m.mask) >> 56) < 6; ) + m.magic = rng.sparse_rand(); + + // A good magic must map every possible occupancy to an index that + // looks up the correct sliding attack in the attacks[s] database. + // Note that we build up the database for square 's' as a side + // effect of verifying the magic. Keep track of the attempt count + // and save it in epoch[], little speed-up trick to avoid resetting + // m.attacks[] after every failed attempt. + for (++cnt, i = 0; i < size; ++i) + { + unsigned idx = m.index(occupancy[i]); + + if (epoch[idx] < cnt) + { + epoch[idx] = cnt; + m.attacks[idx] = reference[i]; + } + else if (m.attacks[idx] != reference[i]) + break; + } + } + } + } +} diff --git a/src/bitboard.h b/src/bitboard.h new file mode 100644 index 0000000..c9f7242 --- /dev/null +++ b/src/bitboard.h @@ -0,0 +1,339 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef BITBOARD_H_INCLUDED +#define BITBOARD_H_INCLUDED + +#include + +#include "types.h" + +namespace Bitbases { + +void init(); +bool probe(Square wksq, Square wpsq, Square bksq, Color us); + +} + +namespace Bitboards { + +void init(); +const std::string pretty(Bitboard b); + +} + +const Bitboard AllSquares = ~Bitboard(0); +const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; + +const Bitboard FileABB = 0x0101010101010101ULL; +const Bitboard FileBBB = FileABB << 1; +const Bitboard FileCBB = FileABB << 2; +const Bitboard FileDBB = FileABB << 3; +const Bitboard FileEBB = FileABB << 4; +const Bitboard FileFBB = FileABB << 5; +const Bitboard FileGBB = FileABB << 6; +const Bitboard FileHBB = FileABB << 7; + +const Bitboard Rank1BB = 0xFF; +const Bitboard Rank2BB = Rank1BB << (8 * 1); +const Bitboard Rank3BB = Rank1BB << (8 * 2); +const Bitboard Rank4BB = Rank1BB << (8 * 3); +const Bitboard Rank5BB = Rank1BB << (8 * 4); +const Bitboard Rank6BB = Rank1BB << (8 * 5); +const Bitboard Rank7BB = Rank1BB << (8 * 6); +const Bitboard Rank8BB = Rank1BB << (8 * 7); + +extern int SquareDistance[SQUARE_NB][SQUARE_NB]; + +extern Bitboard SquareBB[SQUARE_NB]; +extern Bitboard FileBB[FILE_NB]; +extern Bitboard RankBB[RANK_NB]; +extern Bitboard AdjacentFilesBB[FILE_NB]; +extern Bitboard ForwardRanksBB[COLOR_NB][RANK_NB]; +extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB]; +extern Bitboard LineBB[SQUARE_NB][SQUARE_NB]; +extern Bitboard DistanceRingBB[SQUARE_NB][8]; +extern Bitboard ForwardFileBB[COLOR_NB][SQUARE_NB]; +extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB]; +extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB]; +extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; +extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB]; + + +/// Magic holds all magic bitboards relevant data for a single square +struct Magic { + Bitboard mask; + Bitboard magic; + Bitboard* attacks; + unsigned shift; + + // Compute the attack's index using the 'magic bitboards' approach + unsigned index(Bitboard occupied) const { + + if (HasPext) + return unsigned(pext(occupied, mask)); + + if (Is64Bit) + return unsigned(((occupied & mask) * magic) >> shift); + + unsigned lo = unsigned(occupied) & unsigned(mask); + unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32); + return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift; + } +}; + +extern Magic RookMagics[SQUARE_NB]; +extern Magic BishopMagics[SQUARE_NB]; + + +/// Overloads of bitwise operators between a Bitboard and a Square for testing +/// whether a given bit is set in a bitboard, and for setting and clearing bits. + +inline Bitboard operator&(Bitboard b, Square s) { + return b & SquareBB[s]; +} + +inline Bitboard operator|(Bitboard b, Square s) { + return b | SquareBB[s]; +} + +inline Bitboard operator^(Bitboard b, Square s) { + return b ^ SquareBB[s]; +} + +inline Bitboard& operator|=(Bitboard& b, Square s) { + return b |= SquareBB[s]; +} + +inline Bitboard& operator^=(Bitboard& b, Square s) { + return b ^= SquareBB[s]; +} + +constexpr bool more_than_one(Bitboard b) { + return b & (b - 1); +} + +/// rank_bb() and file_bb() return a bitboard representing all the squares on +/// the given file or rank. + +inline Bitboard rank_bb(Rank r) { + return RankBB[r]; +} + +inline Bitboard rank_bb(Square s) { + return RankBB[rank_of(s)]; +} + +inline Bitboard file_bb(File f) { + return FileBB[f]; +} + +inline Bitboard file_bb(Square s) { + return FileBB[file_of(s)]; +} + + +/// shift() moves a bitboard one step along direction D. Mainly for pawns + +template +constexpr Bitboard shift(Bitboard b) { + return D == NORTH ? b << 8 : D == SOUTH ? b >> 8 + : D == NORTH_EAST ? (b & ~FileHBB) << 9 : D == SOUTH_EAST ? (b & ~FileHBB) >> 7 + : D == NORTH_WEST ? (b & ~FileABB) << 7 : D == SOUTH_WEST ? (b & ~FileABB) >> 9 + : 0; +} + + +/// adjacent_files_bb() returns a bitboard representing all the squares on the +/// adjacent files of the given one. + +inline Bitboard adjacent_files_bb(File f) { + return AdjacentFilesBB[f]; +} + + +/// between_bb() returns a bitboard representing all the squares between the two +/// given ones. For instance, between_bb(SQ_C4, SQ_F7) returns a bitboard with +/// the bits for square d5 and e6 set. If s1 and s2 are not on the same rank, file +/// or diagonal, 0 is returned. + +inline Bitboard between_bb(Square s1, Square s2) { + return BetweenBB[s1][s2]; +} + + +/// forward_ranks_bb() returns a bitboard representing all the squares on all the ranks +/// in front of the given one, from the point of view of the given color. For +/// instance, forward_ranks_bb(BLACK, SQ_D3) will return the 16 squares on ranks 1 and 2. + +inline Bitboard forward_ranks_bb(Color c, Square s) { + return ForwardRanksBB[c][rank_of(s)]; +} + + +/// forward_file_bb() returns a bitboard representing all the squares along the line +/// in front of the given one, from the point of view of the given color: +/// ForwardFileBB[c][s] = forward_ranks_bb(c, s) & file_bb(s) + +inline Bitboard forward_file_bb(Color c, Square s) { + return ForwardFileBB[c][s]; +} + + +/// pawn_attack_span() returns a bitboard representing all the squares that can be +/// attacked by a pawn of the given color when it moves along its file, starting +/// from the given square: +/// PawnAttackSpan[c][s] = forward_ranks_bb(c, s) & adjacent_files_bb(file_of(s)); + +inline Bitboard pawn_attack_span(Color c, Square s) { + return PawnAttackSpan[c][s]; +} + + +/// passed_pawn_mask() returns a bitboard mask which can be used to test if a +/// pawn of the given color and on the given square is a passed pawn: +/// PassedPawnMask[c][s] = pawn_attack_span(c, s) | forward_file_bb(c, s) + +inline Bitboard passed_pawn_mask(Color c, Square s) { + return PassedPawnMask[c][s]; +} + + +/// aligned() returns true if the squares s1, s2 and s3 are aligned either on a +/// straight or on a diagonal line. + +inline bool aligned(Square s1, Square s2, Square s3) { + return LineBB[s1][s2] & s3; +} + + +/// distance() functions return the distance between x and y, defined as the +/// number of steps for a king in x to reach y. Works with squares, ranks, files. + +template inline int distance(T x, T y) { return x < y ? y - x : x - y; } +template<> inline int distance(Square x, Square y) { return SquareDistance[x][y]; } + +template inline int distance(T2 x, T2 y); +template<> inline int distance(Square x, Square y) { return distance(file_of(x), file_of(y)); } +template<> inline int distance(Square x, Square y) { return distance(rank_of(x), rank_of(y)); } + + +/// attacks_bb() returns a bitboard representing all the squares attacked by a +/// piece of type Pt (bishop or rook) placed on 's'. + +template +inline Bitboard attacks_bb(Square s, Bitboard occupied) { + + const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s]; + return m.attacks[m.index(occupied)]; +} + +inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) { + + assert(pt != PAWN); + + switch (pt) + { + case BISHOP: return attacks_bb(s, occupied); + case ROOK : return attacks_bb< ROOK>(s, occupied); + case QUEEN : return attacks_bb(s, occupied) | attacks_bb(s, occupied); + default : return PseudoAttacks[pt][s]; + } +} + + +/// popcount() counts the number of non-zero bits in a bitboard + +inline int popcount(Bitboard b) { + +#ifndef USE_POPCNT + + extern uint8_t PopCnt16[1 << 16]; + union { Bitboard bb; uint16_t u[4]; } v = { b }; + return PopCnt16[v.u[0]] + PopCnt16[v.u[1]] + PopCnt16[v.u[2]] + PopCnt16[v.u[3]]; + +#elif defined(_MSC_VER) || defined(__INTEL_COMPILER) + + return (int)_mm_popcnt_u64(b); + +#else // Assumed gcc or compatible compiler + + return __builtin_popcountll(b); + +#endif +} + + +/// lsb() and msb() return the least/most significant bit in a non-zero bitboard + +#if defined(__GNUC__) + +inline Square lsb(Bitboard b) { + assert(b); + return Square(__builtin_ctzll(b)); +} + +inline Square msb(Bitboard b) { + assert(b); + return Square(63 ^ __builtin_clzll(b)); +} + +#elif defined(_WIN64) && defined(_MSC_VER) + +inline Square lsb(Bitboard b) { + assert(b); + unsigned long idx; + _BitScanForward64(&idx, b); + return (Square) idx; +} + +inline Square msb(Bitboard b) { + assert(b); + unsigned long idx; + _BitScanReverse64(&idx, b); + return (Square) idx; +} + +#else + +#define NO_BSF // Fallback on software implementation for other cases + +Square lsb(Bitboard b); +Square msb(Bitboard b); + +#endif + + +/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard + +inline Square pop_lsb(Bitboard* b) { + const Square s = lsb(*b); + *b &= *b - 1; + return s; +} + + +/// frontmost_sq() and backmost_sq() return the square corresponding to the +/// most/least advanced bit relative to the given color. + +inline Square frontmost_sq(Color c, Bitboard b) { return c == WHITE ? msb(b) : lsb(b); } +inline Square backmost_sq(Color c, Bitboard b) { return c == WHITE ? lsb(b) : msb(b); } + +#endif // #ifndef BITBOARD_H_INCLUDED diff --git a/src/endgame.cpp b/src/endgame.cpp new file mode 100644 index 0000000..39db219 --- /dev/null +++ b/src/endgame.cpp @@ -0,0 +1,816 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include + +#include "bitboard.h" +#include "endgame.h" +#include "movegen.h" + +using std::string; + +namespace { + + // Table used to drive the king towards the edge of the board + // in KX vs K and KQ vs KR endgames. + const int PushToEdges[SQUARE_NB] = { + 100, 90, 80, 70, 70, 80, 90, 100, + 90, 70, 60, 50, 50, 60, 70, 90, + 80, 60, 40, 30, 30, 40, 60, 80, + 70, 50, 30, 20, 20, 30, 50, 70, + 70, 50, 30, 20, 20, 30, 50, 70, + 80, 60, 40, 30, 30, 40, 60, 80, + 90, 70, 60, 50, 50, 60, 70, 90, + 100, 90, 80, 70, 70, 80, 90, 100 + }; + + // Table used to drive the king towards a corner square of the + // right color in KBN vs K endgames. + const int PushToCorners[SQUARE_NB] = { + 200, 190, 180, 170, 160, 150, 140, 130, + 190, 180, 170, 160, 150, 140, 130, 140, + 180, 170, 155, 140, 140, 125, 140, 150, + 170, 160, 140, 120, 110, 140, 150, 160, + 160, 150, 140, 110, 120, 140, 160, 170, + 150, 140, 125, 140, 140, 155, 170, 180, + 140, 130, 140, 150, 160, 170, 180, 190, + 130, 140, 150, 160, 170, 180, 190, 200 + }; + + // Tables used to drive a piece towards or away from another piece + const int PushClose[8] = { 0, 0, 100, 80, 60, 40, 20, 10 }; + const int PushAway [8] = { 0, 5, 20, 40, 60, 80, 90, 100 }; + + // Pawn Rank based scaling factors used in KRPPKRP endgame + const int KRPPKRPScaleFactors[RANK_NB] = { 0, 9, 10, 14, 21, 44, 0, 0 }; + +#ifndef NDEBUG + bool verify_material(const Position& pos, Color c, Value npm, int pawnsCnt) { + return pos.non_pawn_material(c) == npm && pos.count(c) == pawnsCnt; + } +#endif + + // Map the square as if strongSide is white and strongSide's only pawn + // is on the left half of the board. + Square normalize(const Position& pos, Color strongSide, Square sq) { + + assert(pos.count(strongSide) == 1); + + if (file_of(pos.square(strongSide)) >= FILE_E) + sq = Square(sq ^ 7); // Mirror SQ_H1 -> SQ_A1 + + if (strongSide == BLACK) + sq = ~sq; + + return sq; + } + +} // namespace + + +/// Endgames members definitions + +Endgames::Endgames() { + + add("KPK"); + add("KNNK"); + add("KBNK"); + add("KRKP"); + add("KRKB"); + add("KRKN"); + add("KQKP"); + add("KQKR"); + + add("KNPK"); + add("KNPKB"); + add("KRPKR"); + add("KRPKB"); + add("KBPKB"); + add("KBPKN"); + add("KBPPKB"); + add("KRPPKRP"); +} + + +/// Mate with KX vs K. This function is used to evaluate positions with +/// king and plenty of material vs a lone king. It simply gives the +/// attacking side a bonus for driving the defending king towards the edge +/// of the board, and for keeping the distance between the two kings small. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, weakSide, VALUE_ZERO, 0)); + assert(!pos.checkers()); // Eval is never called when in check + + // Stalemate detection with lone king + if (pos.side_to_move() == weakSide && !MoveList(pos).size()) + return VALUE_DRAW; + + Square winnerKSq = pos.square(strongSide); + Square loserKSq = pos.square(weakSide); + + Value result = pos.non_pawn_material(strongSide) + + pos.count(strongSide) * PawnValueEg + + PushToEdges[loserKSq] + + PushClose[distance(winnerKSq, loserKSq)]; + + if ( pos.count(strongSide) + || pos.count(strongSide) + ||(pos.count(strongSide) && pos.count(strongSide)) + || ( (pos.pieces(strongSide, BISHOP) & ~DarkSquares) + && (pos.pieces(strongSide, BISHOP) & DarkSquares))) + result = std::min(result + VALUE_KNOWN_WIN, VALUE_MATE_IN_MAX_PLY - 1); + + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// Mate with KBN vs K. This is similar to KX vs K, but we have to drive the +/// defending king towards a corner square of the right color. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, KnightValueMg + BishopValueMg, 0)); + assert(verify_material(pos, weakSide, VALUE_ZERO, 0)); + + Square winnerKSq = pos.square(strongSide); + Square loserKSq = pos.square(weakSide); + Square bishopSq = pos.square(strongSide); + + // kbnk_mate_table() tries to drive toward corners A1 or H8. If we have a + // bishop that cannot reach the above squares, we flip the kings in order + // to drive the enemy toward corners A8 or H1. + if (opposite_colors(bishopSq, SQ_A1)) + { + winnerKSq = ~winnerKSq; + loserKSq = ~loserKSq; + } + + Value result = VALUE_KNOWN_WIN + + PushClose[distance(winnerKSq, loserKSq)] + + PushToCorners[loserKSq]; + + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// KP vs K. This endgame is evaluated with the help of a bitbase. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, VALUE_ZERO, 1)); + assert(verify_material(pos, weakSide, VALUE_ZERO, 0)); + + // Assume strongSide is white and the pawn is on files A-D + Square wksq = normalize(pos, strongSide, pos.square(strongSide)); + Square bksq = normalize(pos, strongSide, pos.square(weakSide)); + Square psq = normalize(pos, strongSide, pos.square(strongSide)); + + Color us = strongSide == pos.side_to_move() ? WHITE : BLACK; + + if (!Bitbases::probe(wksq, psq, bksq, us)) + return VALUE_DRAW; + + Value result = VALUE_KNOWN_WIN + PawnValueEg + Value(rank_of(psq)); + + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// KR vs KP. This is a somewhat tricky endgame to evaluate precisely without +/// a bitbase. The function below returns drawish scores when the pawn is +/// far advanced with support of the king, while the attacking king is far +/// away. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, RookValueMg, 0)); + assert(verify_material(pos, weakSide, VALUE_ZERO, 1)); + + Square wksq = relative_square(strongSide, pos.square(strongSide)); + Square bksq = relative_square(strongSide, pos.square(weakSide)); + Square rsq = relative_square(strongSide, pos.square(strongSide)); + Square psq = relative_square(strongSide, pos.square(weakSide)); + + Square queeningSq = make_square(file_of(psq), RANK_1); + Value result; + + // If the stronger side's king is in front of the pawn, it's a win + if (wksq < psq && file_of(wksq) == file_of(psq)) + result = RookValueEg - distance(wksq, psq); + + // If the weaker side's king is too far from the pawn and the rook, + // it's a win. + else if ( distance(bksq, psq) >= 3 + (pos.side_to_move() == weakSide) + && distance(bksq, rsq) >= 3) + result = RookValueEg - distance(wksq, psq); + + // If the pawn is far advanced and supported by the defending king, + // the position is drawish + else if ( rank_of(bksq) <= RANK_3 + && distance(bksq, psq) == 1 + && rank_of(wksq) >= RANK_4 + && distance(wksq, psq) > 2 + (pos.side_to_move() == strongSide)) + result = Value(80) - 8 * distance(wksq, psq); + + else + result = Value(200) - 8 * ( distance(wksq, psq + SOUTH) + - distance(bksq, psq + SOUTH) + - distance(psq, queeningSq)); + + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// KR vs KB. This is very simple, and always returns drawish scores. The +/// score is slightly bigger when the defending king is close to the edge. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, RookValueMg, 0)); + assert(verify_material(pos, weakSide, BishopValueMg, 0)); + + Value result = Value(PushToEdges[pos.square(weakSide)]); + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// KR vs KN. The attacking side has slightly better winning chances than +/// in KR vs KB, particularly if the king and the knight are far apart. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, RookValueMg, 0)); + assert(verify_material(pos, weakSide, KnightValueMg, 0)); + + Square bksq = pos.square(weakSide); + Square bnsq = pos.square(weakSide); + Value result = Value(PushToEdges[bksq] + PushAway[distance(bksq, bnsq)]); + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// KQ vs KP. In general, this is a win for the stronger side, but there are a +/// few important exceptions. A pawn on 7th rank and on the A,C,F or H files +/// with a king positioned next to it can be a draw, so in that case, we only +/// use the distance between the kings. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, QueenValueMg, 0)); + assert(verify_material(pos, weakSide, VALUE_ZERO, 1)); + + Square winnerKSq = pos.square(strongSide); + Square loserKSq = pos.square(weakSide); + Square pawnSq = pos.square(weakSide); + + Value result = Value(PushClose[distance(winnerKSq, loserKSq)]); + + if ( relative_rank(weakSide, pawnSq) != RANK_7 + || distance(loserKSq, pawnSq) != 1 + || !((FileABB | FileCBB | FileFBB | FileHBB) & pawnSq)) + result += QueenValueEg - PawnValueEg; + + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// KQ vs KR. This is almost identical to KX vs K: We give the attacking +/// king a bonus for having the kings close together, and for forcing the +/// defending king towards the edge. If we also take care to avoid null move for +/// the defending side in the search, this is usually sufficient to win KQ vs KR. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, QueenValueMg, 0)); + assert(verify_material(pos, weakSide, RookValueMg, 0)); + + Square winnerKSq = pos.square(strongSide); + Square loserKSq = pos.square(weakSide); + + Value result = QueenValueEg + - RookValueEg + + PushToEdges[loserKSq] + + PushClose[distance(winnerKSq, loserKSq)]; + + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// Some cases of trivial draws +template<> Value Endgame::operator()(const Position&) const { return VALUE_DRAW; } + + +/// KB and one or more pawns vs K. It checks for draws with rook pawns and +/// a bishop of the wrong color. If such a draw is detected, SCALE_FACTOR_DRAW +/// is returned. If not, the return value is SCALE_FACTOR_NONE, i.e. no scaling +/// will be used. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(pos.non_pawn_material(strongSide) == BishopValueMg); + assert(pos.count(strongSide) >= 1); + + // No assertions about the material of weakSide, because we want draws to + // be detected even when the weaker side has some pawns. + + Bitboard pawns = pos.pieces(strongSide, PAWN); + File pawnsFile = file_of(lsb(pawns)); + + // All pawns are on a single rook file? + if ( (pawnsFile == FILE_A || pawnsFile == FILE_H) + && !(pawns & ~file_bb(pawnsFile))) + { + Square bishopSq = pos.square(strongSide); + Square queeningSq = relative_square(strongSide, make_square(pawnsFile, RANK_8)); + Square kingSq = pos.square(weakSide); + + if ( opposite_colors(queeningSq, bishopSq) + && distance(queeningSq, kingSq) <= 1) + return SCALE_FACTOR_DRAW; + } + + // If all the pawns are on the same B or G file, then it's potentially a draw + if ( (pawnsFile == FILE_B || pawnsFile == FILE_G) + && !(pos.pieces(PAWN) & ~file_bb(pawnsFile)) + && pos.non_pawn_material(weakSide) == 0 + && pos.count(weakSide) >= 1) + { + // Get weakSide pawn that is closest to the home rank + Square weakPawnSq = backmost_sq(weakSide, pos.pieces(weakSide, PAWN)); + + Square strongKingSq = pos.square(strongSide); + Square weakKingSq = pos.square(weakSide); + Square bishopSq = pos.square(strongSide); + + // There's potential for a draw if our pawn is blocked on the 7th rank, + // the bishop cannot attack it or they only have one pawn left + if ( relative_rank(strongSide, weakPawnSq) == RANK_7 + && (pos.pieces(strongSide, PAWN) & (weakPawnSq + pawn_push(weakSide))) + && (opposite_colors(bishopSq, weakPawnSq) || pos.count(strongSide) == 1)) + { + int strongKingDist = distance(weakPawnSq, strongKingSq); + int weakKingDist = distance(weakPawnSq, weakKingSq); + + // It's a draw if the weak king is on its back two ranks, within 2 + // squares of the blocking pawn and the strong king is not + // closer. (I think this rule only fails in practically + // unreachable positions such as 5k1K/6p1/6P1/8/8/3B4/8/8 w + // and positions where qsearch will immediately correct the + // problem such as 8/4k1p1/6P1/1K6/3B4/8/8/8 w) + if ( relative_rank(strongSide, weakKingSq) >= RANK_7 + && weakKingDist <= 2 + && weakKingDist <= strongKingDist) + return SCALE_FACTOR_DRAW; + } + } + + return SCALE_FACTOR_NONE; +} + + +/// KQ vs KR and one or more pawns. It tests for fortress draws with a rook on +/// the third rank defended by a pawn. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, QueenValueMg, 0)); + assert(pos.count(weakSide) == 1); + assert(pos.count(weakSide) >= 1); + + Square kingSq = pos.square(weakSide); + Square rsq = pos.square(weakSide); + + if ( relative_rank(weakSide, kingSq) <= RANK_2 + && relative_rank(weakSide, pos.square(strongSide)) >= RANK_4 + && relative_rank(weakSide, rsq) == RANK_3 + && ( pos.pieces(weakSide, PAWN) + & pos.attacks_from(kingSq) + & pos.attacks_from(rsq, strongSide))) + return SCALE_FACTOR_DRAW; + + return SCALE_FACTOR_NONE; +} + + +/// KRP vs KR. This function knows a handful of the most important classes of +/// drawn positions, but is far from perfect. It would probably be a good idea +/// to add more knowledge in the future. +/// +/// It would also be nice to rewrite the actual code for this function, +/// which is mostly copied from Glaurung 1.x, and isn't very pretty. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, RookValueMg, 1)); + assert(verify_material(pos, weakSide, RookValueMg, 0)); + + // Assume strongSide is white and the pawn is on files A-D + Square wksq = normalize(pos, strongSide, pos.square(strongSide)); + Square bksq = normalize(pos, strongSide, pos.square(weakSide)); + Square wrsq = normalize(pos, strongSide, pos.square(strongSide)); + Square wpsq = normalize(pos, strongSide, pos.square(strongSide)); + Square brsq = normalize(pos, strongSide, pos.square(weakSide)); + + File f = file_of(wpsq); + Rank r = rank_of(wpsq); + Square queeningSq = make_square(f, RANK_8); + int tempo = (pos.side_to_move() == strongSide); + + // If the pawn is not too far advanced and the defending king defends the + // queening square, use the third-rank defence. + if ( r <= RANK_5 + && distance(bksq, queeningSq) <= 1 + && wksq <= SQ_H5 + && (rank_of(brsq) == RANK_6 || (r <= RANK_3 && rank_of(wrsq) != RANK_6))) + return SCALE_FACTOR_DRAW; + + // The defending side saves a draw by checking from behind in case the pawn + // has advanced to the 6th rank with the king behind. + if ( r == RANK_6 + && distance(bksq, queeningSq) <= 1 + && rank_of(wksq) + tempo <= RANK_6 + && (rank_of(brsq) == RANK_1 || (!tempo && distance(brsq, wpsq) >= 3))) + return SCALE_FACTOR_DRAW; + + if ( r >= RANK_6 + && bksq == queeningSq + && rank_of(brsq) == RANK_1 + && (!tempo || distance(wksq, wpsq) >= 2)) + return SCALE_FACTOR_DRAW; + + // White pawn on a7 and rook on a8 is a draw if black's king is on g7 or h7 + // and the black rook is behind the pawn. + if ( wpsq == SQ_A7 + && wrsq == SQ_A8 + && (bksq == SQ_H7 || bksq == SQ_G7) + && file_of(brsq) == FILE_A + && (rank_of(brsq) <= RANK_3 || file_of(wksq) >= FILE_D || rank_of(wksq) <= RANK_5)) + return SCALE_FACTOR_DRAW; + + // If the defending king blocks the pawn and the attacking king is too far + // away, it's a draw. + if ( r <= RANK_5 + && bksq == wpsq + NORTH + && distance(wksq, wpsq) - tempo >= 2 + && distance(wksq, brsq) - tempo >= 2) + return SCALE_FACTOR_DRAW; + + // Pawn on the 7th rank supported by the rook from behind usually wins if the + // attacking king is closer to the queening square than the defending king, + // and the defending king cannot gain tempi by threatening the attacking rook. + if ( r == RANK_7 + && f != FILE_A + && file_of(wrsq) == f + && wrsq != queeningSq + && (distance(wksq, queeningSq) < distance(bksq, queeningSq) - 2 + tempo) + && (distance(wksq, queeningSq) < distance(bksq, wrsq) + tempo)) + return ScaleFactor(SCALE_FACTOR_MAX - 2 * distance(wksq, queeningSq)); + + // Similar to the above, but with the pawn further back + if ( f != FILE_A + && file_of(wrsq) == f + && wrsq < wpsq + && (distance(wksq, queeningSq) < distance(bksq, queeningSq) - 2 + tempo) + && (distance(wksq, wpsq + NORTH) < distance(bksq, wpsq + NORTH) - 2 + tempo) + && ( distance(bksq, wrsq) + tempo >= 3 + || ( distance(wksq, queeningSq) < distance(bksq, wrsq) + tempo + && (distance(wksq, wpsq + NORTH) < distance(bksq, wrsq) + tempo)))) + return ScaleFactor( SCALE_FACTOR_MAX + - 8 * distance(wpsq, queeningSq) + - 2 * distance(wksq, queeningSq)); + + // If the pawn is not far advanced and the defending king is somewhere in + // the pawn's path, it's probably a draw. + if (r <= RANK_4 && bksq > wpsq) + { + if (file_of(bksq) == file_of(wpsq)) + return ScaleFactor(10); + if ( distance(bksq, wpsq) == 1 + && distance(wksq, bksq) > 2) + return ScaleFactor(24 - 2 * distance(wksq, bksq)); + } + return SCALE_FACTOR_NONE; +} + +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, RookValueMg, 1)); + assert(verify_material(pos, weakSide, BishopValueMg, 0)); + + // Test for a rook pawn + if (pos.pieces(PAWN) & (FileABB | FileHBB)) + { + Square ksq = pos.square(weakSide); + Square bsq = pos.square(weakSide); + Square psq = pos.square(strongSide); + Rank rk = relative_rank(strongSide, psq); + Direction push = pawn_push(strongSide); + + // If the pawn is on the 5th rank and the pawn (currently) is on + // the same color square as the bishop then there is a chance of + // a fortress. Depending on the king position give a moderate + // reduction or a stronger one if the defending king is near the + // corner but not trapped there. + if (rk == RANK_5 && !opposite_colors(bsq, psq)) + { + int d = distance(psq + 3 * push, ksq); + + if (d <= 2 && !(d == 0 && ksq == pos.square(strongSide) + 2 * push)) + return ScaleFactor(24); + else + return ScaleFactor(48); + } + + // When the pawn has moved to the 6th rank we can be fairly sure + // it's drawn if the bishop attacks the square in front of the + // pawn from a reasonable distance and the defending king is near + // the corner + if ( rk == RANK_6 + && distance(psq + 2 * push, ksq) <= 1 + && (PseudoAttacks[BISHOP][bsq] & (psq + push)) + && distance(bsq, psq) >= 2) + return ScaleFactor(8); + } + + return SCALE_FACTOR_NONE; +} + +/// KRPP vs KRP. There is just a single rule: if the stronger side has no passed +/// pawns and the defending king is actively placed, the position is drawish. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, RookValueMg, 2)); + assert(verify_material(pos, weakSide, RookValueMg, 1)); + + Square wpsq1 = pos.squares(strongSide)[0]; + Square wpsq2 = pos.squares(strongSide)[1]; + Square bksq = pos.square(weakSide); + + // Does the stronger side have a passed pawn? + if (pos.pawn_passed(strongSide, wpsq1) || pos.pawn_passed(strongSide, wpsq2)) + return SCALE_FACTOR_NONE; + + Rank r = std::max(relative_rank(strongSide, wpsq1), relative_rank(strongSide, wpsq2)); + + if ( distance(bksq, wpsq1) <= 1 + && distance(bksq, wpsq2) <= 1 + && relative_rank(strongSide, bksq) > r) + { + assert(r > RANK_1 && r < RANK_7); + return ScaleFactor(KRPPKRPScaleFactors[r]); + } + return SCALE_FACTOR_NONE; +} + + +/// K and two or more pawns vs K. There is just a single rule here: If all pawns +/// are on the same rook file and are blocked by the defending king, it's a draw. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(pos.non_pawn_material(strongSide) == VALUE_ZERO); + assert(pos.count(strongSide) >= 2); + assert(verify_material(pos, weakSide, VALUE_ZERO, 0)); + + Square ksq = pos.square(weakSide); + Bitboard pawns = pos.pieces(strongSide, PAWN); + + // If all pawns are ahead of the king, on a single rook file and + // the king is within one file of the pawns, it's a draw. + if ( !(pawns & ~forward_ranks_bb(weakSide, ksq)) + && !((pawns & ~FileABB) && (pawns & ~FileHBB)) + && distance(ksq, lsb(pawns)) <= 1) + return SCALE_FACTOR_DRAW; + + return SCALE_FACTOR_NONE; +} + + +/// KBP vs KB. There are two rules: if the defending king is somewhere along the +/// path of the pawn, and the square of the king is not of the same color as the +/// stronger side's bishop, it's a draw. If the two bishops have opposite color, +/// it's almost always a draw. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, BishopValueMg, 1)); + assert(verify_material(pos, weakSide, BishopValueMg, 0)); + + Square pawnSq = pos.square(strongSide); + Square strongBishopSq = pos.square(strongSide); + Square weakBishopSq = pos.square(weakSide); + Square weakKingSq = pos.square(weakSide); + + // Case 1: Defending king blocks the pawn, and cannot be driven away + if ( file_of(weakKingSq) == file_of(pawnSq) + && relative_rank(strongSide, pawnSq) < relative_rank(strongSide, weakKingSq) + && ( opposite_colors(weakKingSq, strongBishopSq) + || relative_rank(strongSide, weakKingSq) <= RANK_6)) + return SCALE_FACTOR_DRAW; + + // Case 2: Opposite colored bishops + if (opposite_colors(strongBishopSq, weakBishopSq)) + { + // We assume that the position is drawn in the following three situations: + // + // a. The pawn is on rank 5 or further back. + // b. The defending king is somewhere in the pawn's path. + // c. The defending bishop attacks some square along the pawn's path, + // and is at least three squares away from the pawn. + // + // These rules are probably not perfect, but in practice they work + // reasonably well. + + if (relative_rank(strongSide, pawnSq) <= RANK_5) + return SCALE_FACTOR_DRAW; + + Bitboard path = forward_file_bb(strongSide, pawnSq); + + if (path & pos.pieces(weakSide, KING)) + return SCALE_FACTOR_DRAW; + + if ( (pos.attacks_from(weakBishopSq) & path) + && distance(weakBishopSq, pawnSq) >= 3) + return SCALE_FACTOR_DRAW; + } + return SCALE_FACTOR_NONE; +} + + +/// KBPP vs KB. It detects a few basic draws with opposite-colored bishops +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, BishopValueMg, 2)); + assert(verify_material(pos, weakSide, BishopValueMg, 0)); + + Square wbsq = pos.square(strongSide); + Square bbsq = pos.square(weakSide); + + if (!opposite_colors(wbsq, bbsq)) + return SCALE_FACTOR_NONE; + + Square ksq = pos.square(weakSide); + Square psq1 = pos.squares(strongSide)[0]; + Square psq2 = pos.squares(strongSide)[1]; + Rank r1 = rank_of(psq1); + Rank r2 = rank_of(psq2); + Square blockSq1, blockSq2; + + if (relative_rank(strongSide, psq1) > relative_rank(strongSide, psq2)) + { + blockSq1 = psq1 + pawn_push(strongSide); + blockSq2 = make_square(file_of(psq2), rank_of(psq1)); + } + else + { + blockSq1 = psq2 + pawn_push(strongSide); + blockSq2 = make_square(file_of(psq1), rank_of(psq2)); + } + + switch (distance(psq1, psq2)) + { + case 0: + // Both pawns are on the same file. It's an easy draw if the defender firmly + // controls some square in the frontmost pawn's path. + if ( file_of(ksq) == file_of(blockSq1) + && relative_rank(strongSide, ksq) >= relative_rank(strongSide, blockSq1) + && opposite_colors(ksq, wbsq)) + return SCALE_FACTOR_DRAW; + else + return SCALE_FACTOR_NONE; + + case 1: + // Pawns on adjacent files. It's a draw if the defender firmly controls the + // square in front of the frontmost pawn's path, and the square diagonally + // behind this square on the file of the other pawn. + if ( ksq == blockSq1 + && opposite_colors(ksq, wbsq) + && ( bbsq == blockSq2 + || (pos.attacks_from(blockSq2) & pos.pieces(weakSide, BISHOP)) + || distance(r1, r2) >= 2)) + return SCALE_FACTOR_DRAW; + + else if ( ksq == blockSq2 + && opposite_colors(ksq, wbsq) + && ( bbsq == blockSq1 + || (pos.attacks_from(blockSq1) & pos.pieces(weakSide, BISHOP)))) + return SCALE_FACTOR_DRAW; + else + return SCALE_FACTOR_NONE; + + default: + // The pawns are not on the same file or adjacent files. No scaling. + return SCALE_FACTOR_NONE; + } +} + + +/// KBP vs KN. There is a single rule: If the defending king is somewhere along +/// the path of the pawn, and the square of the king is not of the same color as +/// the stronger side's bishop, it's a draw. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, BishopValueMg, 1)); + assert(verify_material(pos, weakSide, KnightValueMg, 0)); + + Square pawnSq = pos.square(strongSide); + Square strongBishopSq = pos.square(strongSide); + Square weakKingSq = pos.square(weakSide); + + if ( file_of(weakKingSq) == file_of(pawnSq) + && relative_rank(strongSide, pawnSq) < relative_rank(strongSide, weakKingSq) + && ( opposite_colors(weakKingSq, strongBishopSq) + || relative_rank(strongSide, weakKingSq) <= RANK_6)) + return SCALE_FACTOR_DRAW; + + return SCALE_FACTOR_NONE; +} + + +/// KNP vs K. There is a single rule: if the pawn is a rook pawn on the 7th rank +/// and the defending king prevents the pawn from advancing, the position is drawn. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, KnightValueMg, 1)); + assert(verify_material(pos, weakSide, VALUE_ZERO, 0)); + + // Assume strongSide is white and the pawn is on files A-D + Square pawnSq = normalize(pos, strongSide, pos.square(strongSide)); + Square weakKingSq = normalize(pos, strongSide, pos.square(weakSide)); + + if (pawnSq == SQ_A7 && distance(SQ_A8, weakKingSq) <= 1) + return SCALE_FACTOR_DRAW; + + return SCALE_FACTOR_NONE; +} + + +/// KNP vs KB. If knight can block bishop from taking pawn, it's a win. +/// Otherwise the position is drawn. +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + Square pawnSq = pos.square(strongSide); + Square bishopSq = pos.square(weakSide); + Square weakKingSq = pos.square(weakSide); + + // King needs to get close to promoting pawn to prevent knight from blocking. + // Rules for this are very tricky, so just approximate. + if (forward_file_bb(strongSide, pawnSq) & pos.attacks_from(bishopSq)) + return ScaleFactor(distance(weakKingSq, pawnSq)); + + return SCALE_FACTOR_NONE; +} + + +/// KP vs KP. This is done by removing the weakest side's pawn and probing the +/// KP vs K bitbase: If the weakest side has a draw without the pawn, it probably +/// has at least a draw with the pawn as well. The exception is when the stronger +/// side's pawn is far advanced and not on a rook file; in this case it is often +/// possible to win (e.g. 8/4k3/3p4/3P4/6K1/8/8/8 w - - 0 1). +template<> +ScaleFactor Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, VALUE_ZERO, 1)); + assert(verify_material(pos, weakSide, VALUE_ZERO, 1)); + + // Assume strongSide is white and the pawn is on files A-D + Square wksq = normalize(pos, strongSide, pos.square(strongSide)); + Square bksq = normalize(pos, strongSide, pos.square(weakSide)); + Square psq = normalize(pos, strongSide, pos.square(strongSide)); + + Color us = strongSide == pos.side_to_move() ? WHITE : BLACK; + + // If the pawn has advanced to the fifth rank or further, and is not a + // rook pawn, it's too dangerous to assume that it's at least a draw. + if (rank_of(psq) >= RANK_5 && file_of(psq) != FILE_A) + return SCALE_FACTOR_NONE; + + // Probe the KPK bitbase with the weakest side's pawn removed. If it's a draw, + // it's probably at least a draw even with the pawn. + return Bitbases::probe(wksq, psq, bksq, us) ? SCALE_FACTOR_NONE : SCALE_FACTOR_DRAW; +} diff --git a/src/endgame.h b/src/endgame.h new file mode 100644 index 0000000..b5255a2 --- /dev/null +++ b/src/endgame.h @@ -0,0 +1,125 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef ENDGAME_H_INCLUDED +#define ENDGAME_H_INCLUDED + +#include +#include +#include +#include +#include + +#include "position.h" +#include "types.h" + + +/// EndgameCode lists all supported endgame functions by corresponding codes + +enum EndgameCode { + + EVALUATION_FUNCTIONS, + KNNK, // KNN vs K + KXK, // Generic "mate lone king" eval + KBNK, // KBN vs K + KPK, // KP vs K + KRKP, // KR vs KP + KRKB, // KR vs KB + KRKN, // KR vs KN + KQKP, // KQ vs KP + KQKR, // KQ vs KR + + SCALING_FUNCTIONS, + KBPsK, // KB and pawns vs K + KQKRPs, // KQ vs KR and pawns + KRPKR, // KRP vs KR + KRPKB, // KRP vs KB + KRPPKRP, // KRPP vs KRP + KPsK, // K and pawns vs K + KBPKB, // KBP vs KB + KBPPKB, // KBPP vs KB + KBPKN, // KBP vs KN + KNPK, // KNP vs K + KNPKB, // KNP vs KB + KPKP // KP vs KP +}; + + +/// Endgame functions can be of two types depending on whether they return a +/// Value or a ScaleFactor. +template using +eg_type = typename std::conditional<(E < SCALING_FUNCTIONS), Value, ScaleFactor>::type; + + +/// Base and derived functors for endgame evaluation and scaling functions + +template +struct EndgameBase { + + explicit EndgameBase(Color c) : strongSide(c), weakSide(~c) {} + virtual ~EndgameBase() = default; + virtual T operator()(const Position&) const = 0; + + const Color strongSide, weakSide; +}; + + +template> +struct Endgame : public EndgameBase { + + explicit Endgame(Color c) : EndgameBase(c) {} + T operator()(const Position&) const override; +}; + + +/// The Endgames class stores the pointers to endgame evaluation and scaling +/// base objects in two std::map. We use polymorphism to invoke the actual +/// endgame function by calling its virtual operator(). + +class Endgames { + + template using Ptr = std::unique_ptr>; + template using Map = std::map>; + + template + Map& map() { + return std::get::value>(maps); + } + + template, typename P = Ptr> + void add(const std::string& code) { + + StateInfo st; + map()[Position().set(code, WHITE, &st).material_key()] = P(new Endgame(WHITE)); + map()[Position().set(code, BLACK, &st).material_key()] = P(new Endgame(BLACK)); + } + + std::pair, Map> maps; + +public: + Endgames(); + + template + EndgameBase* probe(Key key) { + return map().count(key) ? map()[key].get() : nullptr; + } +}; + +#endif // #ifndef ENDGAME_H_INCLUDED diff --git a/src/evaluate.cpp b/src/evaluate.cpp new file mode 100644 index 0000000..8d9dd6e --- /dev/null +++ b/src/evaluate.cpp @@ -0,0 +1,952 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include // For std::memset +#include +#include + +#include "bitboard.h" +#include "evaluate.h" +#include "material.h" +#include "pawns.h" + +namespace { + + const Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB); + const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB; + const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB; + const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB; + + const Bitboard KingFlank[FILE_NB] = { + QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide + }; + + namespace Trace { + + enum Tracing {NO_TRACE, TRACE}; + + enum Term { // The first 8 entries are for PieceType + MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, INITIATIVE, TOTAL, TERM_NB + }; + + double scores[TERM_NB][COLOR_NB][PHASE_NB]; + + double to_cp(Value v) { return double(v) / PawnValueEg; } + + void add(int idx, Color c, Score s) { + scores[idx][c][MG] = to_cp(mg_value(s)); + scores[idx][c][EG] = to_cp(eg_value(s)); + } + + void add(int idx, Score w, Score b = SCORE_ZERO) { + add(idx, WHITE, w); add(idx, BLACK, b); + } + + std::ostream& operator<<(std::ostream& os, Term t) { + + if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == INITIATIVE || t == TOTAL) + os << " --- --- | --- --- | "; + else + os << std::setw(5) << scores[t][WHITE][MG] << " " + << std::setw(5) << scores[t][WHITE][EG] << " | " + << std::setw(5) << scores[t][BLACK][MG] << " " + << std::setw(5) << scores[t][BLACK][EG] << " | "; + + os << std::setw(5) << scores[t][WHITE][MG] - scores[t][BLACK][MG] << " " + << std::setw(5) << scores[t][WHITE][EG] - scores[t][BLACK][EG] << " \n"; + + return os; + } + } + + using namespace Trace; + + // Evaluation class contains various information computed and collected + // by the evaluation functions. + template + class Evaluation { + + public: + Evaluation() = delete; + Evaluation(const Position& p) : pos(p) {} + Evaluation& operator=(const Evaluation&) = delete; + + Value value(); + + private: + // Evaluation helpers (used when calling value()) + template void initialize(); + template Score evaluate_king(); + template Score evaluate_threats(); + int king_distance(Color c, Square s); + template Score evaluate_passed_pawns(); + template Score evaluate_space(); + template Score evaluate_pieces(); + ScaleFactor evaluate_scale_factor(Value eg); + Score evaluate_initiative(Value eg); + + // Data members + const Position& pos; + Material::Entry* me; + Pawns::Entry* pe; + Bitboard mobilityArea[COLOR_NB]; + Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO }; + + // attackedBy[color][piece type] is a bitboard representing all squares + // attacked by a given color and piece type. Special "piece types" which are + // also calculated are QUEEN_DIAGONAL and ALL_PIECES. + Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB]; + + // attackedBy2[color] are the squares attacked by 2 pieces of a given color, + // possibly via x-ray or by one pawn and one piece. Diagonal x-ray through + // pawn or squares attacked by 2 pawns are not explicitly added. + Bitboard attackedBy2[COLOR_NB]; + + // kingRing[color] is the zone around the king which is considered + // by the king safety evaluation. This consists of the squares directly + // adjacent to the king, and (only for a king on its first rank) the + // squares two ranks in front of the king. For instance, if black's king + // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8, + // f7, g7, h7, f6, g6 and h6. + Bitboard kingRing[COLOR_NB]; + + // kingAttackersCount[color] is the number of pieces of the given color + // which attack a square in the kingRing of the enemy king. + int kingAttackersCount[COLOR_NB]; + + // kingAttackersWeight[color] is the sum of the "weights" of the pieces of the + // given color which attack a square in the kingRing of the enemy king. The + // weights of the individual piece types are given by the elements in the + // KingAttackWeights array. + int kingAttackersWeight[COLOR_NB]; + + // kingAdjacentZoneAttacksCount[color] is the number of attacks by the given + // color to squares directly adjacent to the enemy king. Pieces which attack + // more than one square are counted multiple times. For instance, if there is + // a white knight on g5 and black's king is on g8, this white knight adds 2 + // to kingAdjacentZoneAttacksCount[WHITE]. + int kingAdjacentZoneAttacksCount[COLOR_NB]; + }; + + #define V(v) Value(v) + #define S(mg, eg) make_score(mg, eg) + + // MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game, + // indexed by piece type and number of attacked squares in the mobility area. + const Score MobilityBonus[][32] = { + { S(-75,-76), S(-57,-54), S( -9,-28), S( -2,-10), S( 6, 5), S( 14, 12), // Knights + S( 22, 26), S( 29, 29), S( 36, 29) }, + { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishops + S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86), + S( 91, 88), S( 98, 97) }, + { S(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rooks + S( 9,112), S( 16,118), S( 30,132), S( 29,142), S( 32,155), S( 38,165), + S( 46,166), S( 48,169), S( 58,171) }, + { S(-39,-36), S(-21,-15), S( 3, 8), S( 3, 18), S( 14, 34), S( 22, 54), // Queens + S( 28, 61), S( 41, 73), S( 43, 79), S( 48, 92), S( 56, 94), S( 60,104), + S( 60,113), S( 66,120), S( 67,123), S( 70,126), S( 71,133), S( 73,136), + S( 79,140), S( 88,143), S( 88,148), S( 99,166), S(102,170), S(102,175), + S(106,184), S(109,191), S(113,206), S(116,212) } + }; + + // Outpost[knight/bishop][supported by pawn] contains bonuses for minor + // pieces if they can reach an outpost square, bigger if that square is + // supported by a pawn. If the minor piece occupies an outpost square + // then score is doubled. + const Score Outpost[][2] = { + { S(22, 6), S(36,12) }, // Knight + { S( 9, 2), S(15, 5) } // Bishop + }; + + // RookOnFile[semiopen/open] contains bonuses for each rook when there is no + // friendly pawn on the rook file. + const Score RookOnFile[] = { S(20, 7), S(45, 20) }; + + // ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to + // which piece type attacks which one. Attacks on lesser pieces which are + // pawn-defended are not considered. + const Score ThreatByMinor[PIECE_TYPE_NB] = { + S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72, 107), S(48, 118) + }; + + const Score ThreatByRook[PIECE_TYPE_NB] = { + S(0, 0), S(0, 25), S(40, 62), S(40, 59), S(0, 34), S(35, 48) + }; + + // ThreatByKing[on one/on many] contains bonuses for king attacks on + // pawns or pieces which are not pawn-defended. + const Score ThreatByKing[] = { S(3, 62), S(9, 138) }; + + // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns. + // We don't use a Score because we process the two components independently. + const Value Passed[][RANK_NB] = { + { V(0), V(5), V( 5), V(31), V(73), V(166), V(252) }, + { V(0), V(7), V(14), V(38), V(73), V(166), V(252) } + }; + + // PassedFile[File] contains a bonus according to the file of a passed pawn + const Score PassedFile[FILE_NB] = { + S( 9, 10), S( 2, 10), S( 1, -8), S(-20,-12), + S(-20,-12), S( 1, -8), S( 2, 10), S( 9, 10) + }; + + // Rank factor applied on some bonus for passed pawn on rank 4 or beyond + const int RankFactor[RANK_NB] = {0, 0, 0, 2, 6, 11, 16}; + + // KingProtector[PieceType-2] contains a bonus according to distance from king + const Score KingProtector[] = { S(-3, -5), S(-4, -3), S(-3, 0), S(-1, 1) }; + + // Assorted bonuses and penalties used by evaluation + const Score MinorBehindPawn = S( 16, 0); + const Score BishopPawns = S( 8, 12); + const Score LongRangedBishop = S( 22, 0); + const Score RookOnPawn = S( 8, 24); + const Score TrappedRook = S( 92, 0); + const Score WeakQueen = S( 50, 10); + const Score CloseEnemies = S( 7, 0); + const Score PawnlessFlank = S( 20, 80); + const Score ThreatBySafePawn = S(192,175); + const Score ThreatByRank = S( 16, 3); + const Score Hanging = S( 48, 27); + const Score WeakUnopposedPawn = S( 5, 25); + const Score ThreatByPawnPush = S( 38, 22); + const Score ThreatByAttackOnQueen = S( 38, 22); + const Score HinderPassedPawn = S( 7, 0); + const Score TrappedBishopA1H1 = S( 50, 50); + + #undef S + #undef V + + // KingAttackWeights[PieceType] contains king attack weights by piece type + const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 }; + + // Penalties for enemy's safe checks + const int QueenSafeCheck = 780; + const int RookSafeCheck = 880; + const int BishopSafeCheck = 435; + const int KnightSafeCheck = 790; + + // Threshold for lazy and space evaluation + const Value LazyThreshold = Value(1500); + const Value SpaceThreshold = Value(12222); + + + // initialize() computes king and pawn attacks, and the king ring bitboard + // for a given color. This is done at the beginning of the evaluation. + + template template + void Evaluation::initialize() { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); + const Direction Down = (Us == WHITE ? SOUTH : NORTH); + const Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB); + + // Find our pawns on the first two ranks, and those which are blocked + Bitboard b = pos.pieces(Us, PAWN) & (shift(pos.pieces()) | LowRanks); + + // Squares occupied by those pawns, by our king, or controlled by enemy pawns + // are excluded from the mobility area. + mobilityArea[Us] = ~(b | pos.square(Us) | pe->pawn_attacks(Them)); + + // Initialise the attack bitboards with the king and pawn information + b = attackedBy[Us][KING] = pos.attacks_from(pos.square(Us)); + attackedBy[Us][PAWN] = pe->pawn_attacks(Us); + + attackedBy2[Us] = b & attackedBy[Us][PAWN]; + attackedBy[Us][ALL_PIECES] = b | attackedBy[Us][PAWN]; + + // Init our king safety tables only if we are going to use them + if (pos.non_pawn_material(Them) >= RookValueMg + KnightValueMg) + { + kingRing[Us] = b; + if (relative_rank(Us, pos.square(Us)) == RANK_1) + kingRing[Us] |= shift(b); + + kingAttackersCount[Them] = popcount(b & pe->pawn_attacks(Them)); + kingAdjacentZoneAttacksCount[Them] = kingAttackersWeight[Them] = 0; + } + else + kingRing[Us] = kingAttackersCount[Them] = 0; + } + + + // evaluate_pieces() assigns bonuses and penalties to the pieces of a given + // color and type. + + template template + Score Evaluation::evaluate_pieces() { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB + : Rank5BB | Rank4BB | Rank3BB); + const Square* pl = pos.squares(Us); + + Bitboard b, bb; + Square s; + Score score = SCORE_ZERO; + + attackedBy[Us][Pt] = 0; + + if (Pt == QUEEN) + attackedBy[Us][QUEEN_DIAGONAL] = 0; + + while ((s = *pl++) != SQ_NONE) + { + // Find attacked squares, including x-ray attacks for bishops and rooks + b = Pt == BISHOP ? attacks_bb(s, pos.pieces() ^ pos.pieces(QUEEN)) + : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK)) + : pos.attacks_from(s); + + if (pos.pinned_pieces(Us) & s) + b &= LineBB[pos.square(Us)][s]; + + attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b; + attackedBy[Us][ALL_PIECES] |= attackedBy[Us][Pt] |= b; + + if (Pt == QUEEN) + attackedBy[Us][QUEEN_DIAGONAL] |= b & PseudoAttacks[BISHOP][s]; + + if (b & kingRing[Them]) + { + kingAttackersCount[Us]++; + kingAttackersWeight[Us] += KingAttackWeights[Pt]; + kingAdjacentZoneAttacksCount[Us] += popcount(b & attackedBy[Them][KING]); + } + + int mob = popcount(b & mobilityArea[Us]); + + mobility[Us] += MobilityBonus[Pt - 2][mob]; + + // Bonus for this piece as a king protector + score += KingProtector[Pt - 2] * distance(s, pos.square(Us)); + + if (Pt == BISHOP || Pt == KNIGHT) + { + // Bonus for outpost squares + bb = OutpostRanks & ~pe->pawn_attacks_span(Them); + if (bb & s) + score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & s)] * 2; + else + { + bb &= b & ~pos.pieces(Us); + if (bb) + score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & bb)]; + } + + // Bonus when behind a pawn + if ( relative_rank(Us, s) < RANK_5 + && (pos.pieces(PAWN) & (s + pawn_push(Us)))) + score += MinorBehindPawn; + + if (Pt == BISHOP) + { + // Penalty for pawns on the same color square as the bishop + score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s); + + // Bonus for bishop on a long diagonal which can "see" both center squares + if (more_than_one(Center & (attacks_bb(s, pos.pieces(PAWN)) | s))) + score += LongRangedBishop; + } + + // An important Chess960 pattern: A cornered bishop blocked by a friendly + // pawn diagonally in front of it is a very serious problem, especially + // when that pawn is also blocked. + if ( Pt == BISHOP + && pos.is_chess960() + && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))) + { + Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST); + if (pos.piece_on(s + d) == make_piece(Us, PAWN)) + score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4 + : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2 + : TrappedBishopA1H1; + } + } + + if (Pt == ROOK) + { + // Bonus for aligning with enemy pawns on the same rank/file + if (relative_rank(Us, s) >= RANK_5) + score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]); + + // Bonus when on an open or semi-open file + if (pe->semiopen_file(Us, file_of(s))) + score += RookOnFile[bool(pe->semiopen_file(Them, file_of(s)))]; + + // Penalty when trapped by the king, even more if the king cannot castle + else if (mob <= 3) + { + Square ksq = pos.square(Us); + + if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq))) + && !pe->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq))) + score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us)); + } + } + + if (Pt == QUEEN) + { + // Penalty if any relative pin or discovered attack against the queen + Bitboard pinners; + if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, pinners)) + score -= WeakQueen; + } + } + + if (T) + Trace::add(Pt, Us, score); + + return score; + } + + + // evaluate_king() assigns bonuses and penalties to a king of a given color + + template template + Score Evaluation::evaluate_king() { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB + : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB); + + const Square ksq = pos.square(Us); + Bitboard weak, b, b1, b2, safe, unsafeChecks; + + // King shelter and enemy pawns storm + Score score = pe->king_safety(pos, ksq); + + // Main king safety evaluation + if (kingAttackersCount[Them] > (1 - pos.count(Them))) + { + // Attacked squares defended at most once by our queen or king + weak = attackedBy[Them][ALL_PIECES] + & ~attackedBy2[Us] + & (attackedBy[Us][KING] | attackedBy[Us][QUEEN] | ~attackedBy[Us][ALL_PIECES]); + + int kingDanger = unsafeChecks = 0; + + // Analyse the safe enemy's checks which are possible on next move + safe = ~pos.pieces(Them); + safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]); + + b1 = attacks_bb(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN)); + b2 = attacks_bb(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN)); + + // Enemy queen safe checks + if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN]) + kingDanger += QueenSafeCheck; + + b1 &= attackedBy[Them][ROOK]; + b2 &= attackedBy[Them][BISHOP]; + + // Enemy rooks checks + if (b1 & safe) + kingDanger += RookSafeCheck; + else + unsafeChecks |= b1; + + // Enemy bishops checks + if (b2 & safe) + kingDanger += BishopSafeCheck; + else + unsafeChecks |= b2; + + // Enemy knights checks + b = pos.attacks_from(ksq) & attackedBy[Them][KNIGHT]; + if (b & safe) + kingDanger += KnightSafeCheck; + else + unsafeChecks |= b; + + // Unsafe or occupied checking squares will also be considered, as long as + // the square is in the attacker's mobility area. + unsafeChecks &= mobilityArea[Them]; + + kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them] + + 102 * kingAdjacentZoneAttacksCount[Them] + + 191 * popcount(kingRing[Us] & weak) + + 143 * popcount(pos.pinned_pieces(Us) | unsafeChecks) + - 848 * !pos.count(Them) + - 9 * mg_value(score) / 8 + + 40; + + // Transform the kingDanger units into a Score, and subtract it from the evaluation + if (kingDanger > 0) + { + int mobilityDanger = mg_value(mobility[Them] - mobility[Us]); + kingDanger = std::max(0, kingDanger + mobilityDanger); + score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16); + } + } + + // King tropism: firstly, find squares that opponent attacks in our king flank + File kf = file_of(ksq); + b = attackedBy[Them][ALL_PIECES] & KingFlank[kf] & Camp; + + assert(((Us == WHITE ? b << 4 : b >> 4) & b) == 0); + assert(popcount(Us == WHITE ? b << 4 : b >> 4) == popcount(b)); + + // Secondly, add the squares which are attacked twice in that flank and + // which are not defended by our pawns. + b = (Us == WHITE ? b << 4 : b >> 4) + | (b & attackedBy2[Them] & ~attackedBy[Us][PAWN]); + + score -= CloseEnemies * popcount(b); + + // Penalty when our king is on a pawnless flank + if (!(pos.pieces(PAWN) & KingFlank[kf])) + score -= PawnlessFlank; + + if (T) + Trace::add(KING, Us, score); + + return score; + } + + + // evaluate_threats() assigns bonuses according to the types of the attacking + // and the attacked pieces. + + template template + Score Evaluation::evaluate_threats() { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); + const Direction Left = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); + const Direction Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST); + const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); + + Bitboard b, weak, defended, stronglyProtected, safeThreats; + Score score = SCORE_ZERO; + + // Non-pawn enemies attacked by a pawn + weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & attackedBy[Us][PAWN]; + + if (weak) + { + b = pos.pieces(Us, PAWN) & ( ~attackedBy[Them][ALL_PIECES] + | attackedBy[Us][ALL_PIECES]); + + safeThreats = (shift(b) | shift(b)) & weak; + + score += ThreatBySafePawn * popcount(safeThreats); + } + + // Squares strongly protected by the opponent, either because they attack the + // square with a pawn, or because they attack the square twice and we don't. + stronglyProtected = attackedBy[Them][PAWN] + | (attackedBy2[Them] & ~attackedBy2[Us]); + + // Non-pawn enemies, strongly protected + defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) + & stronglyProtected; + + // Enemies not strongly protected and under our attack + weak = pos.pieces(Them) + & ~stronglyProtected + & attackedBy[Us][ALL_PIECES]; + + // Add a bonus according to the kind of attacking pieces + if (defended | weak) + { + b = (defended | weak) & (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP]); + while (b) + { + Square s = pop_lsb(&b); + score += ThreatByMinor[type_of(pos.piece_on(s))]; + if (type_of(pos.piece_on(s)) != PAWN) + score += ThreatByRank * (int)relative_rank(Them, s); + } + + b = (pos.pieces(Them, QUEEN) | weak) & attackedBy[Us][ROOK]; + while (b) + { + Square s = pop_lsb(&b); + score += ThreatByRook[type_of(pos.piece_on(s))]; + if (type_of(pos.piece_on(s)) != PAWN) + score += ThreatByRank * (int)relative_rank(Them, s); + } + + score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]); + + b = weak & attackedBy[Us][KING]; + if (b) + score += ThreatByKing[more_than_one(b)]; + } + + // Bonus for opponent unopposed weak pawns + if (pos.pieces(Us, ROOK, QUEEN)) + score += WeakUnopposedPawn * pe->weak_unopposed(Them); + + // Find squares where our pawns can push on the next move + b = shift(pos.pieces(Us, PAWN)) & ~pos.pieces(); + b |= shift(b & TRank3BB) & ~pos.pieces(); + + // Keep only the squares which are not completely unsafe + b &= ~attackedBy[Them][PAWN] + & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]); + + // Add a bonus for each new pawn threats from those squares + b = (shift(b) | shift(b)) + & pos.pieces(Them) + & ~attackedBy[Us][PAWN]; + + score += ThreatByPawnPush * popcount(b); + + // Add a bonus for safe slider attack threats on opponent queen + safeThreats = ~pos.pieces(Us) & ~attackedBy2[Them] & attackedBy2[Us]; + b = (attackedBy[Us][BISHOP] & attackedBy[Them][QUEEN_DIAGONAL]) + | (attackedBy[Us][ROOK ] & attackedBy[Them][QUEEN] & ~attackedBy[Them][QUEEN_DIAGONAL]); + + score += ThreatByAttackOnQueen * popcount(b & safeThreats); + + if (T) + Trace::add(THREAT, Us, score); + + return score; + } + + // helper used by evaluate_passed_pawns to cap the distance + template + int Evaluation::king_distance(Color c, Square s) { + return std::min(distance(pos.square(c), s), 5); + } + + // evaluate_passed_pawns() evaluates the passed pawns and candidate passed + // pawns of the given color. + + template template + Score Evaluation::evaluate_passed_pawns() { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); + + Bitboard b, bb, squaresToQueen, defendedSquares, unsafeSquares; + Score score = SCORE_ZERO; + + b = pe->passed_pawns(Us); + + while (b) + { + Square s = pop_lsb(&b); + + assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up))); + + bb = forward_file_bb(Us, s) & (attackedBy[Them][ALL_PIECES] | pos.pieces(Them)); + score -= HinderPassedPawn * popcount(bb); + + int r = relative_rank(Us, s); + int rr = RankFactor[r]; + + Value mbonus = Passed[MG][r], ebonus = Passed[EG][r]; + + if (rr) + { + Square blockSq = s + Up; + + // Adjust bonus based on the king's proximity + ebonus += (king_distance(Them, blockSq) * 5 - king_distance(Us, blockSq) * 2) * rr; + + // If blockSq is not the queening square then consider also a second push + if (r != RANK_7) + ebonus -= king_distance(Us, blockSq + Up) * rr; + + // If the pawn is free to advance, then increase the bonus + if (pos.empty(blockSq)) + { + // If there is a rook or queen attacking/defending the pawn from behind, + // consider all the squaresToQueen. Otherwise consider only the squares + // in the pawn's path attacked or occupied by the enemy. + defendedSquares = unsafeSquares = squaresToQueen = forward_file_bb(Us, s); + + bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from(s); + + if (!(pos.pieces(Us) & bb)) + defendedSquares &= attackedBy[Us][ALL_PIECES]; + + if (!(pos.pieces(Them) & bb)) + unsafeSquares &= attackedBy[Them][ALL_PIECES] | pos.pieces(Them); + + // If there aren't any enemy attacks, assign a big bonus. Otherwise + // assign a smaller bonus if the block square isn't attacked. + int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0; + + // If the path to the queen is fully defended, assign a big bonus. + // Otherwise assign a smaller bonus if the block square is defended. + if (defendedSquares == squaresToQueen) + k += 6; + + else if (defendedSquares & blockSq) + k += 4; + + mbonus += k * rr, ebonus += k * rr; + } + else if (pos.pieces(Us) & blockSq) + mbonus += rr + r * 2, ebonus += rr + r * 2; + } // rr != 0 + + // Scale down bonus for candidate passers which need more than one + // pawn push to become passed or have a pawn in front of them. + if (!pos.pawn_passed(Us, s + Up) || (pos.pieces(PAWN) & forward_file_bb(Us, s))) + mbonus /= 2, ebonus /= 2; + + score += make_score(mbonus, ebonus) + PassedFile[file_of(s)]; + } + + if (T) + Trace::add(PASSED, Us, score); + + return score; + } + + + // evaluate_space() computes the space evaluation for a given side. The + // space evaluation is a simple bonus based on the number of safe squares + // available for minor pieces on the central four files on ranks 2--4. Safe + // squares one, two or three squares behind a friendly pawn are counted + // twice. Finally, the space bonus is multiplied by a weight. The aim is to + // improve play on game opening. + + template template + Score Evaluation::evaluate_space() { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Bitboard SpaceMask = + Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB) + : CenterFiles & (Rank7BB | Rank6BB | Rank5BB); + + // Find the safe squares for our pieces inside the area defined by + // SpaceMask. A square is unsafe if it is attacked by an enemy + // pawn, or if it is undefended and attacked by an enemy piece. + Bitboard safe = SpaceMask + & ~pos.pieces(Us, PAWN) + & ~attackedBy[Them][PAWN] + & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]); + + // Find all squares which are at most three squares behind some friendly pawn + Bitboard behind = pos.pieces(Us, PAWN); + behind |= (Us == WHITE ? behind >> 8 : behind << 8); + behind |= (Us == WHITE ? behind >> 16 : behind << 16); + + // Since SpaceMask[Us] is fully on our half of the board... + assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0); + + // ...count safe + (behind & safe) with a single popcount. + int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + int weight = pos.count(Us) - 2 * pe->open_files(); + + return make_score(bonus * weight * weight / 16, 0); + } + + + // evaluate_initiative() computes the initiative correction value for the + // position, i.e., second order bonus/malus based on the known attacking/defending + // status of the players. + + template + Score Evaluation::evaluate_initiative(Value eg) { + + int kingDistance = distance(pos.square(WHITE), pos.square(BLACK)) + - distance(pos.square(WHITE), pos.square(BLACK)); + bool bothFlanks = (pos.pieces(PAWN) & QueenSide) && (pos.pieces(PAWN) & KingSide); + + // Compute the initiative bonus for the attacking side + int initiative = 8 * (pe->pawn_asymmetry() + kingDistance - 17) + 12 * pos.count() + 16 * bothFlanks; + + // Now apply the bonus: note that we find the attacking side by extracting + // the sign of the endgame value, and that we carefully cap the bonus so + // that the endgame score will never change sign after the bonus. + int v = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg)); + + if (T) + Trace::add(INITIATIVE, make_score(0, v)); + + return make_score(0, v); + } + + + // evaluate_scale_factor() computes the scale factor for the winning side + + template + ScaleFactor Evaluation::evaluate_scale_factor(Value eg) { + + Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK; + ScaleFactor sf = me->scale_factor(pos, strongSide); + + // If we don't already have an unusual scale factor, check for certain + // types of endgames, and use a lower scale for those. + if (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN) + { + if (pos.opposite_bishops()) + { + // Endgame with opposite-colored bishops and no other pieces (ignoring pawns) + // is almost a draw, in case of KBP vs KB, it is even more a draw. + if ( pos.non_pawn_material(WHITE) == BishopValueMg + && pos.non_pawn_material(BLACK) == BishopValueMg) + return more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9); + + // Endgame with opposite-colored bishops, but also other pieces. Still + // a bit drawish, but not as drawish as with only the two bishops. + return ScaleFactor(46); + } + // Endings where weaker side can place his king in front of the opponent's + // pawns are drawish. + else if ( abs(eg) <= BishopValueEg + && pos.count(strongSide) <= 2 + && !pos.pawn_passed(~strongSide, pos.square(~strongSide))) + return ScaleFactor(37 + 7 * pos.count(strongSide)); + } + + return sf; + } + + + // value() is the main function of the class. It computes the various parts of + // the evaluation and returns the value of the position from the point of view + // of the side to move. + + template + Value Evaluation::value() { + + assert(!pos.checkers()); + + // Probe the material hash table + me = Material::probe(pos); + + // If we have a specialized evaluation function for the current material + // configuration, call it and return. + if (me->specialized_eval_exists()) + return me->evaluate(pos); + + // Initialize score by reading the incrementally updated scores included in + // the position object (material + piece square tables) and the material + // imbalance. Score is computed internally from the white point of view. + Score score = pos.psq_score() + me->imbalance() + Eval::Contempt; + + // Probe the pawn hash table + pe = Pawns::probe(pos); + score += pe->pawns_score(); + + // Early exit if score is high + Value v = (mg_value(score) + eg_value(score)) / 2; + if (abs(v) > LazyThreshold) + return pos.side_to_move() == WHITE ? v : -v; + + // Main evaluation begins here + + initialize(); + initialize(); + + score += evaluate_pieces() - evaluate_pieces(); + score += evaluate_pieces() - evaluate_pieces(); + score += evaluate_pieces() - evaluate_pieces(); + score += evaluate_pieces() - evaluate_pieces(); + + score += mobility[WHITE] - mobility[BLACK]; + + score += evaluate_king() + - evaluate_king(); + + score += evaluate_threats() + - evaluate_threats(); + + score += evaluate_passed_pawns() + - evaluate_passed_pawns(); + + if (pos.non_pawn_material() >= SpaceThreshold) + score += evaluate_space() + - evaluate_space(); + + score += evaluate_initiative(eg_value(score)); + + // Interpolate between a middlegame and a (scaled by 'sf') endgame score + ScaleFactor sf = evaluate_scale_factor(eg_value(score)); + v = mg_value(score) * int(me->game_phase()) + + eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL; + + v /= int(PHASE_MIDGAME); + + // In case of tracing add all remaining individual evaluation terms + if (T) + { + Trace::add(MATERIAL, pos.psq_score()); + Trace::add(IMBALANCE, me->imbalance()); + Trace::add(PAWN, pe->pawns_score()); + Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]); + if (pos.non_pawn_material() >= SpaceThreshold) + Trace::add(SPACE, evaluate_space() + , evaluate_space()); + Trace::add(TOTAL, score); + } + + return pos.side_to_move() == WHITE ? v : -v; // Side to move point of view + } + +} // namespace + +Score Eval::Contempt = SCORE_ZERO; + +/// evaluate() is the evaluator for the outer world. It returns a static evaluation +/// of the position from the point of view of the side to move. + +Value Eval::evaluate(const Position& pos) +{ + return Evaluation<>(pos).value() + Eval::Tempo; +} + +/// trace() is like evaluate(), but instead of returning a value, it returns +/// a string (suitable for outputting to stdout) that contains the detailed +/// descriptions and values of each evaluation term. Useful for debugging. + +std::string Eval::trace(const Position& pos) { + + std::memset(scores, 0, sizeof(scores)); + + Value v = Evaluation(pos).value() + Eval::Tempo; + v = pos.side_to_move() == WHITE ? v : -v; // White's point of view + + std::stringstream ss; + ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2) + << " Eval term | White | Black | Total \n" + << " | MG EG | MG EG | MG EG \n" + << "----------------+-------------+-------------+-------------\n" + << " Material | " << Term(MATERIAL) + << " Imbalance | " << Term(IMBALANCE) + << " Pawns | " << Term(PAWN) + << " Knights | " << Term(KNIGHT) + << " Bishops | " << Term(BISHOP) + << " Rooks | " << Term(ROOK) + << " Queens | " << Term(QUEEN) + << " Mobility | " << Term(MOBILITY) + << " King safety | " << Term(KING) + << " Threats | " << Term(THREAT) + << " Passed pawns | " << Term(PASSED) + << " Space | " << Term(SPACE) + << " Initiative | " << Term(INITIATIVE) + << "----------------+-------------+-------------+-------------\n" + << " Total | " << Term(TOTAL); + + ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n"; + + return ss.str(); +} diff --git a/src/evaluate.h b/src/evaluate.h new file mode 100644 index 0000000..eef888d --- /dev/null +++ b/src/evaluate.h @@ -0,0 +1,41 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef EVALUATE_H_INCLUDED +#define EVALUATE_H_INCLUDED + +#include + +#include "types.h" + +class Position; + +namespace Eval { + +const Value Tempo = Value(20); // Must be visible to search + +extern Score Contempt; + +std::string trace(const Position& pos); + +Value evaluate(const Position& pos); +} + +#endif // #ifndef EVALUATE_H_INCLUDED diff --git a/src/main.cpp b/src/main.cpp new file mode 100644 index 0000000..aad09ce --- /dev/null +++ b/src/main.cpp @@ -0,0 +1,55 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include + +#include "bitboard.h" +#include "position.h" +#include "search.h" +#include "thread.h" +#include "tt.h" +#include "uci.h" +#include "syzygy/tbprobe.h" + +namespace PSQT { + void init(); +} + +int main(int argc, char* argv[]) { + + std::cout << engine_info() << std::endl; + + UCI::init(Options); + PSQT::init(); + Bitboards::init(); + Position::init(); + Bitbases::init(); + Search::init(); + Pawns::init(); + Tablebases::init(Options["SyzygyPath"]); + TT.resize(Options["Hash"]); + Threads.set(Options["Threads"]); + Search::clear(); // After threads are up + + UCI::loop(argc, argv); + + Threads.set(0); + return 0; +} diff --git a/src/material.cpp b/src/material.cpp new file mode 100644 index 0000000..fb39209 --- /dev/null +++ b/src/material.cpp @@ -0,0 +1,228 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include // For std::min +#include +#include // For std::memset + +#include "material.h" +#include "thread.h" + +using namespace std; + +namespace { + + // Polynomial material imbalance parameters + + const int QuadraticOurs[][PIECE_TYPE_NB] = { + // OUR PIECES + // pair pawn knight bishop rook queen + {1667 }, // Bishop pair + { 40, 0 }, // Pawn + { 32, 255, -3 }, // Knight OUR PIECES + { 0, 104, 4, 0 }, // Bishop + { -26, -2, 47, 105, -149 }, // Rook + {-189, 24, 117, 133, -134, -10 } // Queen + }; + + const int QuadraticTheirs[][PIECE_TYPE_NB] = { + // THEIR PIECES + // pair pawn knight bishop rook queen + { 0 }, // Bishop pair + { 36, 0 }, // Pawn + { 9, 63, 0 }, // Knight OUR PIECES + { 59, 65, 42, 0 }, // Bishop + { 46, 39, 24, -24, 0 }, // Rook + { 97, 100, -42, 137, 268, 0 } // Queen + }; + + // Endgame evaluation and scaling functions are accessed directly and not through + // the function maps because they correspond to more than one material hash key. + Endgame EvaluateKXK[] = { Endgame(WHITE), Endgame(BLACK) }; + + Endgame ScaleKBPsK[] = { Endgame(WHITE), Endgame(BLACK) }; + Endgame ScaleKQKRPs[] = { Endgame(WHITE), Endgame(BLACK) }; + Endgame ScaleKPsK[] = { Endgame(WHITE), Endgame(BLACK) }; + Endgame ScaleKPKP[] = { Endgame(WHITE), Endgame(BLACK) }; + + // Helper used to detect a given material distribution + bool is_KXK(const Position& pos, Color us) { + return !more_than_one(pos.pieces(~us)) + && pos.non_pawn_material(us) >= RookValueMg; + } + + bool is_KBPsKs(const Position& pos, Color us) { + return pos.non_pawn_material(us) == BishopValueMg + && pos.count(us) == 1 + && pos.count(us) >= 1; + } + + bool is_KQKRPs(const Position& pos, Color us) { + return !pos.count(us) + && pos.non_pawn_material(us) == QueenValueMg + && pos.count(us) == 1 + && pos.count(~us) == 1 + && pos.count(~us) >= 1; + } + + /// imbalance() calculates the imbalance by comparing the piece count of each + /// piece type for both colors. + template + int imbalance(const int pieceCount[][PIECE_TYPE_NB]) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + + int bonus = 0; + + // Second-degree polynomial material imbalance, by Tord Romstad + for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) + { + if (!pieceCount[Us][pt1]) + continue; + + int v = 0; + + for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2) + v += QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2] + + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2]; + + bonus += pieceCount[Us][pt1] * v; + } + + return bonus; + } + +} // namespace + +namespace Material { + +/// Material::probe() looks up the current position's material configuration in +/// the material hash table. It returns a pointer to the Entry if the position +/// is found. Otherwise a new Entry is computed and stored there, so we don't +/// have to recompute all when the same material configuration occurs again. + +Entry* probe(const Position& pos) { + + Key key = pos.material_key(); + Entry* e = pos.this_thread()->materialTable[key]; + + if (e->key == key) + return e; + + std::memset(e, 0, sizeof(Entry)); + e->key = key; + e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL; + + Value npm_w = pos.non_pawn_material(WHITE); + Value npm_b = pos.non_pawn_material(BLACK); + Value npm = std::max(EndgameLimit, std::min(npm_w + npm_b, MidgameLimit)); + + // Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME] + e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit)); + + // Let's look if we have a specialized evaluation function for this particular + // material configuration. Firstly we look for a fixed configuration one, then + // for a generic one if the previous search failed. + if ((e->evaluationFunction = pos.this_thread()->endgames.probe(key)) != nullptr) + return e; + + for (Color c = WHITE; c <= BLACK; ++c) + if (is_KXK(pos, c)) + { + e->evaluationFunction = &EvaluateKXK[c]; + return e; + } + + // OK, we didn't find any special evaluation function for the current material + // configuration. Is there a suitable specialized scaling function? + EndgameBase* sf; + + if ((sf = pos.this_thread()->endgames.probe(key)) != nullptr) + { + e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned + return e; + } + + // We didn't find any specialized scaling function, so fall back on generic + // ones that refer to more than one material distribution. Note that in this + // case we don't return after setting the function. + for (Color c = WHITE; c <= BLACK; ++c) + { + if (is_KBPsKs(pos, c)) + e->scalingFunction[c] = &ScaleKBPsK[c]; + + else if (is_KQKRPs(pos, c)) + e->scalingFunction[c] = &ScaleKQKRPs[c]; + } + + if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board + { + if (!pos.count(BLACK)) + { + assert(pos.count(WHITE) >= 2); + + e->scalingFunction[WHITE] = &ScaleKPsK[WHITE]; + } + else if (!pos.count(WHITE)) + { + assert(pos.count(BLACK) >= 2); + + e->scalingFunction[BLACK] = &ScaleKPsK[BLACK]; + } + else if (pos.count(WHITE) == 1 && pos.count(BLACK) == 1) + { + // This is a special case because we set scaling functions + // for both colors instead of only one. + e->scalingFunction[WHITE] = &ScaleKPKP[WHITE]; + e->scalingFunction[BLACK] = &ScaleKPKP[BLACK]; + } + } + + // Zero or just one pawn makes it difficult to win, even with a small material + // advantage. This catches some trivial draws like KK, KBK and KNK and gives a + // drawish scale factor for cases such as KRKBP and KmmKm (except for KBBKN). + if (!pos.count(WHITE) && npm_w - npm_b <= BishopValueMg) + e->factor[WHITE] = uint8_t(npm_w < RookValueMg ? SCALE_FACTOR_DRAW : + npm_b <= BishopValueMg ? 4 : 14); + + if (!pos.count(BLACK) && npm_b - npm_w <= BishopValueMg) + e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW : + npm_w <= BishopValueMg ? 4 : 14); + + if (pos.count(WHITE) == 1 && npm_w - npm_b <= BishopValueMg) + e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN; + + if (pos.count(BLACK) == 1 && npm_b - npm_w <= BishopValueMg) + e->factor[BLACK] = (uint8_t) SCALE_FACTOR_ONEPAWN; + + // Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder + // for the bishop pair "extended piece", which allows us to be more flexible + // in defining bishop pair bonuses. + const int PieceCount[COLOR_NB][PIECE_TYPE_NB] = { + { pos.count(WHITE) > 1, pos.count(WHITE), pos.count(WHITE), + pos.count(WHITE) , pos.count(WHITE), pos.count(WHITE) }, + { pos.count(BLACK) > 1, pos.count(BLACK), pos.count(BLACK), + pos.count(BLACK) , pos.count(BLACK), pos.count(BLACK) } }; + + e->value = int16_t((imbalance(PieceCount) - imbalance(PieceCount)) / 16); + return e; +} + +} // namespace Material diff --git a/src/material.h b/src/material.h new file mode 100644 index 0000000..7fea5e7 --- /dev/null +++ b/src/material.h @@ -0,0 +1,73 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef MATERIAL_H_INCLUDED +#define MATERIAL_H_INCLUDED + +#include "endgame.h" +#include "misc.h" +#include "position.h" +#include "types.h" + +namespace Material { + +/// Material::Entry contains various information about a material configuration. +/// It contains a material imbalance evaluation, a function pointer to a special +/// endgame evaluation function (which in most cases is NULL, meaning that the +/// standard evaluation function will be used), and scale factors. +/// +/// The scale factors are used to scale the evaluation score up or down. For +/// instance, in KRB vs KR endgames, the score is scaled down by a factor of 4, +/// which will result in scores of absolute value less than one pawn. + +struct Entry { + + Score imbalance() const { return make_score(value, value); } + Phase game_phase() const { return gamePhase; } + bool specialized_eval_exists() const { return evaluationFunction != nullptr; } + Value evaluate(const Position& pos) const { return (*evaluationFunction)(pos); } + + // scale_factor takes a position and a color as input and returns a scale factor + // for the given color. We have to provide the position in addition to the color + // because the scale factor may also be a function which should be applied to + // the position. For instance, in KBP vs K endgames, the scaling function looks + // for rook pawns and wrong-colored bishops. + ScaleFactor scale_factor(const Position& pos, Color c) const { + ScaleFactor sf = scalingFunction[c] ? (*scalingFunction[c])(pos) + : SCALE_FACTOR_NONE; + return sf != SCALE_FACTOR_NONE ? sf : ScaleFactor(factor[c]); + } + + Key key; + EndgameBase* evaluationFunction; + EndgameBase* scalingFunction[COLOR_NB]; // Could be one for each + // side (e.g. KPKP, KBPsKs) + int16_t value; + uint8_t factor[COLOR_NB]; + Phase gamePhase; +}; + +typedef HashTable Table; + +Entry* probe(const Position& pos); + +} // namespace Material + +#endif // #ifndef MATERIAL_H_INCLUDED diff --git a/src/misc.cpp b/src/misc.cpp new file mode 100644 index 0000000..2eb62f3 --- /dev/null +++ b/src/misc.cpp @@ -0,0 +1,317 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifdef _WIN32 +#if _WIN32_WINNT < 0x0601 +#undef _WIN32_WINNT +#define _WIN32_WINNT 0x0601 // Force to include needed API prototypes +#endif +#include +// The needed Windows API for processor groups could be missed from old Windows +// versions, so instead of calling them directly (forcing the linker to resolve +// the calls at compile time), try to load them at runtime. To do this we need +// first to define the corresponding function pointers. +extern "C" { +typedef bool(*fun1_t)(LOGICAL_PROCESSOR_RELATIONSHIP, + PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX, PDWORD); +typedef bool(*fun2_t)(USHORT, PGROUP_AFFINITY); +typedef bool(*fun3_t)(HANDLE, CONST GROUP_AFFINITY*, PGROUP_AFFINITY); +} +#endif + +#include +#include +#include +#include +#include + +#include "misc.h" +#include "thread.h" + +using namespace std; + +namespace { + +/// Version number. If Version is left empty, then compile date in the format +/// DD-MM-YY and show in engine_info. +const string Version = "9"; + +/// Our fancy logging facility. The trick here is to replace cin.rdbuf() and +/// cout.rdbuf() with two Tie objects that tie cin and cout to a file stream. We +/// can toggle the logging of std::cout and std:cin at runtime whilst preserving +/// usual I/O functionality, all without changing a single line of code! +/// Idea from http://groups.google.com/group/comp.lang.c++/msg/1d941c0f26ea0d81 + +struct Tie: public streambuf { // MSVC requires split streambuf for cin and cout + + Tie(streambuf* b, streambuf* l) : buf(b), logBuf(l) {} + + int sync() override { return logBuf->pubsync(), buf->pubsync(); } + int overflow(int c) override { return log(buf->sputc((char)c), "<< "); } + int underflow() override { return buf->sgetc(); } + int uflow() override { return log(buf->sbumpc(), ">> "); } + + streambuf *buf, *logBuf; + + int log(int c, const char* prefix) { + + static int last = '\n'; // Single log file + + if (last == '\n') + logBuf->sputn(prefix, 3); + + return last = logBuf->sputc((char)c); + } +}; + +class Logger { + + Logger() : in(cin.rdbuf(), file.rdbuf()), out(cout.rdbuf(), file.rdbuf()) {} + ~Logger() { start(""); } + + ofstream file; + Tie in, out; + +public: + static void start(const std::string& fname) { + + static Logger l; + + if (!fname.empty() && !l.file.is_open()) + { + l.file.open(fname, ifstream::out); + cin.rdbuf(&l.in); + cout.rdbuf(&l.out); + } + else if (fname.empty() && l.file.is_open()) + { + cout.rdbuf(l.out.buf); + cin.rdbuf(l.in.buf); + l.file.close(); + } + } +}; + +} // namespace + +/// engine_info() returns the full name of the current Stockfish version. This +/// will be either "Stockfish DD-MM-YY" (where DD-MM-YY is the date when +/// the program was compiled) or "Stockfish ", depending on whether +/// Version is empty. + +const string engine_info(bool to_uci) { + + const string months("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec"); + string month, day, year; + stringstream ss, date(__DATE__); // From compiler, format is "Sep 21 2008" + + ss << "Stockfish " << Version << setfill('0'); + + if (Version.empty()) + { + date >> month >> day >> year; + ss << setw(2) << day << setw(2) << (1 + months.find(month) / 4) << year.substr(2); + } + + ss << (Is64Bit ? " 64" : "") + << (HasPext ? " BMI2" : (HasPopCnt ? " POPCNT" : "")) + << (to_uci ? "\nid author ": " by ") + << "T. Romstad, M. Costalba, J. Kiiski, G. Linscott"; + + return ss.str(); +} + + +/// Debug functions used mainly to collect run-time statistics +static int64_t hits[2], means[2]; + +void dbg_hit_on(bool b) { ++hits[0]; if (b) ++hits[1]; } +void dbg_hit_on(bool c, bool b) { if (c) dbg_hit_on(b); } +void dbg_mean_of(int v) { ++means[0]; means[1] += v; } + +void dbg_print() { + + if (hits[0]) + cerr << "Total " << hits[0] << " Hits " << hits[1] + << " hit rate (%) " << 100 * hits[1] / hits[0] << endl; + + if (means[0]) + cerr << "Total " << means[0] << " Mean " + << (double)means[1] / means[0] << endl; +} + + +/// Used to serialize access to std::cout to avoid multiple threads writing at +/// the same time. + +std::ostream& operator<<(std::ostream& os, SyncCout sc) { + + static Mutex m; + + if (sc == IO_LOCK) + m.lock(); + + if (sc == IO_UNLOCK) + m.unlock(); + + return os; +} + + +/// Trampoline helper to avoid moving Logger to misc.h +void start_logger(const std::string& fname) { Logger::start(fname); } + + +/// prefetch() preloads the given address in L1/L2 cache. This is a non-blocking +/// function that doesn't stall the CPU waiting for data to be loaded from memory, +/// which can be quite slow. +#ifdef NO_PREFETCH + +void prefetch(void*) {} + +#else + +void prefetch(void* addr) { + +# if defined(__INTEL_COMPILER) + // This hack prevents prefetches from being optimized away by + // Intel compiler. Both MSVC and gcc seem not be affected by this. + __asm__ (""); +# endif + +# if defined(__INTEL_COMPILER) || defined(_MSC_VER) + _mm_prefetch((char*)addr, _MM_HINT_T0); +# else + __builtin_prefetch(addr); +# endif +} + +#endif + +void prefetch2(void* addr) { + + prefetch(addr); + prefetch((uint8_t*)addr + 64); +} + +namespace WinProcGroup { + +#ifndef _WIN32 + +void bindThisThread(size_t) {} + +#else + +/// get_group() retrieves logical processor information using Windows specific +/// API and returns the best group id for the thread with index idx. Original +/// code from Texel by Peter Österlund. + +int get_group(size_t idx) { + + int threads = 0; + int nodes = 0; + int cores = 0; + DWORD returnLength = 0; + DWORD byteOffset = 0; + + // Early exit if the needed API is not available at runtime + HMODULE k32 = GetModuleHandle("Kernel32.dll"); + auto fun1 = (fun1_t)GetProcAddress(k32, "GetLogicalProcessorInformationEx"); + if (!fun1) + return -1; + + // First call to get returnLength. We expect it to fail due to null buffer + if (fun1(RelationAll, nullptr, &returnLength)) + return -1; + + // Once we know returnLength, allocate the buffer + SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *buffer, *ptr; + ptr = buffer = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX*)malloc(returnLength); + + // Second call, now we expect to succeed + if (!fun1(RelationAll, buffer, &returnLength)) + { + free(buffer); + return -1; + } + + while (ptr->Size > 0 && byteOffset + ptr->Size <= returnLength) + { + if (ptr->Relationship == RelationNumaNode) + nodes++; + + else if (ptr->Relationship == RelationProcessorCore) + { + cores++; + threads += (ptr->Processor.Flags == LTP_PC_SMT) ? 2 : 1; + } + + byteOffset += ptr->Size; + ptr = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX*)(((char*)ptr) + ptr->Size); + } + + free(buffer); + + std::vector groups; + + // Run as many threads as possible on the same node until core limit is + // reached, then move on filling the next node. + for (int n = 0; n < nodes; n++) + for (int i = 0; i < cores / nodes; i++) + groups.push_back(n); + + // In case a core has more than one logical processor (we assume 2) and we + // have still threads to allocate, then spread them evenly across available + // nodes. + for (int t = 0; t < threads - cores; t++) + groups.push_back(t % nodes); + + // If we still have more threads than the total number of logical processors + // then return -1 and let the OS to decide what to do. + return idx < groups.size() ? groups[idx] : -1; +} + + +/// bindThisThread() set the group affinity of the current thread + +void bindThisThread(size_t idx) { + + // Use only local variables to be thread-safe + int group = get_group(idx); + + if (group == -1) + return; + + // Early exit if the needed API are not available at runtime + HMODULE k32 = GetModuleHandle("Kernel32.dll"); + auto fun2 = (fun2_t)GetProcAddress(k32, "GetNumaNodeProcessorMaskEx"); + auto fun3 = (fun3_t)GetProcAddress(k32, "SetThreadGroupAffinity"); + + if (!fun2 || !fun3) + return; + + GROUP_AFFINITY affinity; + if (fun2(group, &affinity)) + fun3(GetCurrentThread(), &affinity, nullptr); +} + +#endif + +} // namespace WinProcGroup diff --git a/src/misc.h b/src/misc.h new file mode 100644 index 0000000..563a58a --- /dev/null +++ b/src/misc.h @@ -0,0 +1,112 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef MISC_H_INCLUDED +#define MISC_H_INCLUDED + +#include +#include +#include +#include +#include + +#include "types.h" + +const std::string engine_info(bool to_uci = false); +void prefetch(void* addr); +void prefetch2(void* addr); +void start_logger(const std::string& fname); + +void dbg_hit_on(bool b); +void dbg_hit_on(bool c, bool b); +void dbg_mean_of(int v); +void dbg_print(); + +typedef std::chrono::milliseconds::rep TimePoint; // A value in milliseconds + +inline TimePoint now() { + return std::chrono::duration_cast + (std::chrono::steady_clock::now().time_since_epoch()).count(); +} + +template +struct HashTable { + Entry* operator[](Key key) { return &table[(uint32_t)key & (Size - 1)]; } + +private: + std::vector table = std::vector(Size); +}; + + +enum SyncCout { IO_LOCK, IO_UNLOCK }; +std::ostream& operator<<(std::ostream&, SyncCout); + +#define sync_cout std::cout << IO_LOCK +#define sync_endl std::endl << IO_UNLOCK + + +/// xorshift64star Pseudo-Random Number Generator +/// This class is based on original code written and dedicated +/// to the public domain by Sebastiano Vigna (2014). +/// It has the following characteristics: +/// +/// - Outputs 64-bit numbers +/// - Passes Dieharder and SmallCrush test batteries +/// - Does not require warm-up, no zeroland to escape +/// - Internal state is a single 64-bit integer +/// - Period is 2^64 - 1 +/// - Speed: 1.60 ns/call (Core i7 @3.40GHz) +/// +/// For further analysis see +/// + +class PRNG { + + uint64_t s; + + uint64_t rand64() { + + s ^= s >> 12, s ^= s << 25, s ^= s >> 27; + return s * 2685821657736338717LL; + } + +public: + PRNG(uint64_t seed) : s(seed) { assert(seed); } + + template T rand() { return T(rand64()); } + + /// Special generator used to fast init magic numbers. + /// Output values only have 1/8th of their bits set on average. + template T sparse_rand() + { return T(rand64() & rand64() & rand64()); } +}; + + +/// Under Windows it is not possible for a process to run on more than one +/// logical processor group. This usually means to be limited to use max 64 +/// cores. To overcome this, some special platform specific API should be +/// called to set group affinity for each thread. Original code from Texel by +/// Peter Österlund. + +namespace WinProcGroup { + void bindThisThread(size_t idx); +} + +#endif // #ifndef MISC_H_INCLUDED diff --git a/src/movegen.cpp b/src/movegen.cpp new file mode 100644 index 0000000..15de166 --- /dev/null +++ b/src/movegen.cpp @@ -0,0 +1,420 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include + +#include "movegen.h" +#include "position.h" + +namespace { + + template + ExtMove* generate_castling(const Position& pos, ExtMove* moveList, Color us) { + + static const bool KingSide = (Cr == WHITE_OO || Cr == BLACK_OO); + + if (pos.castling_impeded(Cr) || !pos.can_castle(Cr)) + return moveList; + + // After castling, the rook and king final positions are the same in Chess960 + // as they would be in standard chess. + Square kfrom = pos.square(us); + Square rfrom = pos.castling_rook_square(Cr); + Square kto = relative_square(us, KingSide ? SQ_G1 : SQ_C1); + Bitboard enemies = pos.pieces(~us); + + assert(!pos.checkers()); + + const Direction K = Chess960 ? kto > kfrom ? WEST : EAST + : KingSide ? WEST : EAST; + + for (Square s = kto; s != kfrom; s += K) + if (pos.attackers_to(s) & enemies) + return moveList; + + // Because we generate only legal castling moves we need to verify that + // when moving the castling rook we do not discover some hidden checker. + // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1. + if (Chess960 && (attacks_bb(kto, pos.pieces() ^ rfrom) & pos.pieces(~us, ROOK, QUEEN))) + return moveList; + + Move m = make(kfrom, rfrom); + + if (Checks && !pos.gives_check(m)) + return moveList; + + *moveList++ = m; + return moveList; + } + + + template + ExtMove* make_promotions(ExtMove* moveList, Square to, Square ksq) { + + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) + *moveList++ = make(to - D, to, QUEEN); + + if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS) + { + *moveList++ = make(to - D, to, ROOK); + *moveList++ = make(to - D, to, BISHOP); + *moveList++ = make(to - D, to, KNIGHT); + } + + // Knight promotion is the only promotion that can give a direct check + // that's not already included in the queen promotion. + if (Type == QUIET_CHECKS && (PseudoAttacks[KNIGHT][to] & ksq)) + *moveList++ = make(to - D, to, KNIGHT); + else + (void)ksq; // Silence a warning under MSVC + + return moveList; + } + + + template + ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard target) { + + // Compute our parametrized parameters at compile time, named according to + // the point of view of white side. + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB); + const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); + const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); + const Direction Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST); + const Direction Left = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); + + Bitboard emptySquares; + + Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB; + Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB; + + Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target: + Type == CAPTURES ? target : pos.pieces(Them)); + + // Single and double pawn pushes, no promotions + if (Type != CAPTURES) + { + emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces()); + + Bitboard b1 = shift(pawnsNotOn7) & emptySquares; + Bitboard b2 = shift(b1 & TRank3BB) & emptySquares; + + if (Type == EVASIONS) // Consider only blocking squares + { + b1 &= target; + b2 &= target; + } + + if (Type == QUIET_CHECKS) + { + Square ksq = pos.square(Them); + + b1 &= pos.attacks_from(ksq, Them); + b2 &= pos.attacks_from(ksq, Them); + + // Add pawn pushes which give discovered check. This is possible only + // if the pawn is not on the same file as the enemy king, because we + // don't generate captures. Note that a possible discovery check + // promotion has been already generated amongst the captures. + Bitboard dcCandidates = pos.discovered_check_candidates(); + if (pawnsNotOn7 & dcCandidates) + { + Bitboard dc1 = shift(pawnsNotOn7 & dcCandidates) & emptySquares & ~file_bb(ksq); + Bitboard dc2 = shift(dc1 & TRank3BB) & emptySquares; + + b1 |= dc1; + b2 |= dc2; + } + } + + while (b1) + { + Square to = pop_lsb(&b1); + *moveList++ = make_move(to - Up, to); + } + + while (b2) + { + Square to = pop_lsb(&b2); + *moveList++ = make_move(to - Up - Up, to); + } + } + + // Promotions and underpromotions + if (pawnsOn7 && (Type != EVASIONS || (target & TRank8BB))) + { + if (Type == CAPTURES) + emptySquares = ~pos.pieces(); + + if (Type == EVASIONS) + emptySquares &= target; + + Bitboard b1 = shift(pawnsOn7) & enemies; + Bitboard b2 = shift(pawnsOn7) & enemies; + Bitboard b3 = shift(pawnsOn7) & emptySquares; + + Square ksq = pos.square(Them); + + while (b1) + moveList = make_promotions(moveList, pop_lsb(&b1), ksq); + + while (b2) + moveList = make_promotions(moveList, pop_lsb(&b2), ksq); + + while (b3) + moveList = make_promotions(moveList, pop_lsb(&b3), ksq); + } + + // Standard and en-passant captures + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) + { + Bitboard b1 = shift(pawnsNotOn7) & enemies; + Bitboard b2 = shift(pawnsNotOn7) & enemies; + + while (b1) + { + Square to = pop_lsb(&b1); + *moveList++ = make_move(to - Right, to); + } + + while (b2) + { + Square to = pop_lsb(&b2); + *moveList++ = make_move(to - Left, to); + } + + if (pos.ep_square() != SQ_NONE) + { + assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6)); + + // An en passant capture can be an evasion only if the checking piece + // is the double pushed pawn and so is in the target. Otherwise this + // is a discovery check and we are forced to do otherwise. + if (Type == EVASIONS && !(target & (pos.ep_square() - Up))) + return moveList; + + b1 = pawnsNotOn7 & pos.attacks_from(pos.ep_square(), Them); + + assert(b1); + + while (b1) + *moveList++ = make(pop_lsb(&b1), pos.ep_square()); + } + } + + return moveList; + } + + + template + ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Color us, + Bitboard target) { + + assert(Pt != KING && Pt != PAWN); + + const Square* pl = pos.squares(us); + + for (Square from = *pl; from != SQ_NONE; from = *++pl) + { + if (Checks) + { + if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN) + && !(PseudoAttacks[Pt][from] & target & pos.check_squares(Pt))) + continue; + + if (pos.discovered_check_candidates() & from) + continue; + } + + Bitboard b = pos.attacks_from(from) & target; + + if (Checks) + b &= pos.check_squares(Pt); + + while (b) + *moveList++ = make_move(from, pop_lsb(&b)); + } + + return moveList; + } + + + template + ExtMove* generate_all(const Position& pos, ExtMove* moveList, Bitboard target) { + + const bool Checks = Type == QUIET_CHECKS; + + moveList = generate_pawn_moves(pos, moveList, target); + moveList = generate_moves(pos, moveList, Us, target); + moveList = generate_moves(pos, moveList, Us, target); + moveList = generate_moves< ROOK, Checks>(pos, moveList, Us, target); + moveList = generate_moves< QUEEN, Checks>(pos, moveList, Us, target); + + if (Type != QUIET_CHECKS && Type != EVASIONS) + { + Square ksq = pos.square(Us); + Bitboard b = pos.attacks_from(ksq) & target; + while (b) + *moveList++ = make_move(ksq, pop_lsb(&b)); + } + + if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(Us)) + { + if (pos.is_chess960()) + { + moveList = generate_castling::right, Checks, true>(pos, moveList, Us); + moveList = generate_castling::right, Checks, true>(pos, moveList, Us); + } + else + { + moveList = generate_castling::right, Checks, false>(pos, moveList, Us); + moveList = generate_castling::right, Checks, false>(pos, moveList, Us); + } + } + + return moveList; + } + +} // namespace + + +/// generate generates all pseudo-legal captures and queen +/// promotions. Returns a pointer to the end of the move list. +/// +/// generate generates all pseudo-legal non-captures and +/// underpromotions. Returns a pointer to the end of the move list. +/// +/// generate generates all pseudo-legal captures and +/// non-captures. Returns a pointer to the end of the move list. + +template +ExtMove* generate(const Position& pos, ExtMove* moveList) { + + assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS); + assert(!pos.checkers()); + + Color us = pos.side_to_move(); + + Bitboard target = Type == CAPTURES ? pos.pieces(~us) + : Type == QUIETS ? ~pos.pieces() + : Type == NON_EVASIONS ? ~pos.pieces(us) : 0; + + return us == WHITE ? generate_all(pos, moveList, target) + : generate_all(pos, moveList, target); +} + +// Explicit template instantiations +template ExtMove* generate(const Position&, ExtMove*); +template ExtMove* generate(const Position&, ExtMove*); +template ExtMove* generate(const Position&, ExtMove*); + + +/// generate generates all pseudo-legal non-captures and knight +/// underpromotions that give check. Returns a pointer to the end of the move list. +template<> +ExtMove* generate(const Position& pos, ExtMove* moveList) { + + assert(!pos.checkers()); + + Color us = pos.side_to_move(); + Bitboard dc = pos.discovered_check_candidates(); + + while (dc) + { + Square from = pop_lsb(&dc); + PieceType pt = type_of(pos.piece_on(from)); + + if (pt == PAWN) + continue; // Will be generated together with direct checks + + Bitboard b = pos.attacks_from(pt, from) & ~pos.pieces(); + + if (pt == KING) + b &= ~PseudoAttacks[QUEEN][pos.square(~us)]; + + while (b) + *moveList++ = make_move(from, pop_lsb(&b)); + } + + return us == WHITE ? generate_all(pos, moveList, ~pos.pieces()) + : generate_all(pos, moveList, ~pos.pieces()); +} + + +/// generate generates all pseudo-legal check evasions when the side +/// to move is in check. Returns a pointer to the end of the move list. +template<> +ExtMove* generate(const Position& pos, ExtMove* moveList) { + + assert(pos.checkers()); + + Color us = pos.side_to_move(); + Square ksq = pos.square(us); + Bitboard sliderAttacks = 0; + Bitboard sliders = pos.checkers() & ~pos.pieces(KNIGHT, PAWN); + + // Find all the squares attacked by slider checkers. We will remove them from + // the king evasions in order to skip known illegal moves, which avoids any + // useless legality checks later on. + while (sliders) + { + Square checksq = pop_lsb(&sliders); + sliderAttacks |= LineBB[checksq][ksq] ^ checksq; + } + + // Generate evasions for king, capture and non capture moves + Bitboard b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks; + while (b) + *moveList++ = make_move(ksq, pop_lsb(&b)); + + if (more_than_one(pos.checkers())) + return moveList; // Double check, only a king move can save the day + + // Generate blocking evasions or captures of the checking piece + Square checksq = lsb(pos.checkers()); + Bitboard target = between_bb(checksq, ksq) | checksq; + + return us == WHITE ? generate_all(pos, moveList, target) + : generate_all(pos, moveList, target); +} + + +/// generate generates all the legal moves in the given position + +template<> +ExtMove* generate(const Position& pos, ExtMove* moveList) { + + Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); + Square ksq = pos.square(pos.side_to_move()); + ExtMove* cur = moveList; + + moveList = pos.checkers() ? generate(pos, moveList) + : generate(pos, moveList); + while (cur != moveList) + if ( (pinned || from_sq(*cur) == ksq || type_of(*cur) == ENPASSANT) + && !pos.legal(*cur)) + *cur = (--moveList)->move; + else + ++cur; + + return moveList; +} diff --git a/src/movegen.h b/src/movegen.h new file mode 100644 index 0000000..9bf2a46 --- /dev/null +++ b/src/movegen.h @@ -0,0 +1,75 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef MOVEGEN_H_INCLUDED +#define MOVEGEN_H_INCLUDED + +#include + +#include "types.h" + +class Position; + +enum GenType { + CAPTURES, + QUIETS, + QUIET_CHECKS, + EVASIONS, + NON_EVASIONS, + LEGAL +}; + +struct ExtMove { + Move move; + int value; + + operator Move() const { return move; } + void operator=(Move m) { move = m; } + + // Inhibit unwanted implicit conversions to Move + // with an ambiguity that yields to a compile error. + operator float() const = delete; +}; + +inline bool operator<(const ExtMove& f, const ExtMove& s) { + return f.value < s.value; +} + +template +ExtMove* generate(const Position& pos, ExtMove* moveList); + +/// The MoveList struct is a simple wrapper around generate(). It sometimes comes +/// in handy to use this class instead of the low level generate() function. +template +struct MoveList { + + explicit MoveList(const Position& pos) : last(generate(pos, moveList)) {} + const ExtMove* begin() const { return moveList; } + const ExtMove* end() const { return last; } + size_t size() const { return last - moveList; } + bool contains(Move move) const { + return std::find(begin(), end(), move) != end(); + } + +private: + ExtMove moveList[MAX_MOVES], *last; +}; + +#endif // #ifndef MOVEGEN_H_INCLUDED diff --git a/src/movepick.cpp b/src/movepick.cpp new file mode 100644 index 0000000..ab247b7 --- /dev/null +++ b/src/movepick.cpp @@ -0,0 +1,334 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include + +#include "movepick.h" + +namespace { + + enum Stages { + MAIN_SEARCH, CAPTURES_INIT, GOOD_CAPTURES, KILLERS, COUNTERMOVE, QUIET_INIT, QUIET, BAD_CAPTURES, + EVASION, EVASIONS_INIT, ALL_EVASIONS, + PROBCUT, PROBCUT_INIT, PROBCUT_CAPTURES, + QSEARCH_WITH_CHECKS, QCAPTURES_1_INIT, QCAPTURES_1, QCHECKS, + QSEARCH_NO_CHECKS, QCAPTURES_2_INIT, QCAPTURES_2, + QSEARCH_RECAPTURES, QRECAPTURES + }; + + // partial_insertion_sort() sorts moves in descending order up to and including + // a given limit. The order of moves smaller than the limit is left unspecified. + void partial_insertion_sort(ExtMove* begin, ExtMove* end, int limit) { + + for (ExtMove *sortedEnd = begin, *p = begin + 1; p < end; ++p) + if (p->value >= limit) + { + ExtMove tmp = *p, *q; + *p = *++sortedEnd; + for (q = sortedEnd; q != begin && *(q - 1) < tmp; --q) + *q = *(q - 1); + *q = tmp; + } + } + + // pick_best() finds the best move in the range (begin, end) and moves it to + // the front. It's faster than sorting all the moves in advance when there + // are few moves, e.g., the possible captures. + Move pick_best(ExtMove* begin, ExtMove* end) { + + std::swap(*begin, *std::max_element(begin, end)); + return *begin; + } + +} // namespace + + +/// Constructors of the MovePicker class. As arguments we pass information +/// to help it to return the (presumably) good moves first, to decide which +/// moves to return (in the quiescence search, for instance, we only want to +/// search captures, promotions, and some checks) and how important good move +/// ordering is at the current node. + +/// MovePicker constructor for the main search +MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, + const CapturePieceToHistory* cph, const PieceToHistory** ch, Move cm, Move* killers_p) + : pos(p), mainHistory(mh), captureHistory(cph), contHistory(ch), countermove(cm), + killers{killers_p[0], killers_p[1]}, depth(d){ + + assert(d > DEPTH_ZERO); + + stage = pos.checkers() ? EVASION : MAIN_SEARCH; + ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; + stage += (ttMove == MOVE_NONE); +} + +/// MovePicker constructor for quiescence search +MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, const CapturePieceToHistory* cph, Square s) + : pos(p), mainHistory(mh), captureHistory(cph) { + + assert(d <= DEPTH_ZERO); + + if (pos.checkers()) + stage = EVASION; + + else if (d > DEPTH_QS_NO_CHECKS) + stage = QSEARCH_WITH_CHECKS; + + else if (d > DEPTH_QS_RECAPTURES) + stage = QSEARCH_NO_CHECKS; + + else + { + stage = QSEARCH_RECAPTURES; + recaptureSquare = s; + return; + } + + ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; + stage += (ttMove == MOVE_NONE); +} + +/// MovePicker constructor for ProbCut: we generate captures with SEE higher +/// than or equal to the given threshold. +MovePicker::MovePicker(const Position& p, Move ttm, Value th, const CapturePieceToHistory* cph) + : pos(p), captureHistory(cph), threshold(th) { + + assert(!pos.checkers()); + + stage = PROBCUT; + ttMove = ttm + && pos.pseudo_legal(ttm) + && pos.capture(ttm) + && pos.see_ge(ttm, threshold) ? ttm : MOVE_NONE; + + stage += (ttMove == MOVE_NONE); +} + +/// score() assigns a numerical value to each move in a list, used for sorting. +/// Captures are ordered by Most Valuable Victim (MVV), preferring captures +/// with a good history. Quiets are ordered using the histories. +template +void MovePicker::score() { + + static_assert(Type == CAPTURES || Type == QUIETS || Type == EVASIONS, "Wrong type"); + + for (auto& m : *this) + if (Type == CAPTURES) + m.value = PieceValue[MG][pos.piece_on(to_sq(m))] + + Value((*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))]); + + else if (Type == QUIETS) + m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] + + (*contHistory[0])[pos.moved_piece(m)][to_sq(m)] + + (*contHistory[1])[pos.moved_piece(m)][to_sq(m)] + + (*contHistory[3])[pos.moved_piece(m)][to_sq(m)]; + + else // Type == EVASIONS + { + if (pos.capture(m)) + m.value = PieceValue[MG][pos.piece_on(to_sq(m))] + - Value(type_of(pos.moved_piece(m))); + else + m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] - (1 << 28); + } +} + +/// next_move() is the most important method of the MovePicker class. It returns +/// a new pseudo legal move every time it is called, until there are no more moves +/// left. It picks the move with the biggest value from a list of generated moves +/// taking care not to return the ttMove if it has already been searched. + +Move MovePicker::next_move(bool skipQuiets) { + + Move move; + + switch (stage) { + + case MAIN_SEARCH: case EVASION: case QSEARCH_WITH_CHECKS: + case QSEARCH_NO_CHECKS: case PROBCUT: + ++stage; + return ttMove; + + case CAPTURES_INIT: + endBadCaptures = cur = moves; + endMoves = generate(pos, cur); + score(); + ++stage; + /* fallthrough */ + + case GOOD_CAPTURES: + while (cur < endMoves) + { + move = pick_best(cur++, endMoves); + if (move != ttMove) + { + if (pos.see_ge(move, Value(-55 * (cur-1)->value / 1024))) + return move; + + // Losing capture, move it to the beginning of the array + *endBadCaptures++ = move; + } + } + + ++stage; + move = killers[0]; // First killer move + if ( move != MOVE_NONE + && move != ttMove + && pos.pseudo_legal(move) + && !pos.capture(move)) + return move; + /* fallthrough */ + + case KILLERS: + ++stage; + move = killers[1]; // Second killer move + if ( move != MOVE_NONE + && move != ttMove + && pos.pseudo_legal(move) + && !pos.capture(move)) + return move; + /* fallthrough */ + + case COUNTERMOVE: + ++stage; + move = countermove; + if ( move != MOVE_NONE + && move != ttMove + && move != killers[0] + && move != killers[1] + && pos.pseudo_legal(move) + && !pos.capture(move)) + return move; + /* fallthrough */ + + case QUIET_INIT: + cur = endBadCaptures; + endMoves = generate(pos, cur); + score(); + partial_insertion_sort(cur, endMoves, -4000 * depth / ONE_PLY); + ++stage; + /* fallthrough */ + + case QUIET: + while ( cur < endMoves + && (!skipQuiets || cur->value >= VALUE_ZERO)) + { + move = *cur++; + + if ( move != ttMove + && move != killers[0] + && move != killers[1] + && move != countermove) + return move; + } + ++stage; + cur = moves; // Point to beginning of bad captures + /* fallthrough */ + + case BAD_CAPTURES: + if (cur < endBadCaptures) + return *cur++; + break; + + case EVASIONS_INIT: + cur = moves; + endMoves = generate(pos, cur); + score(); + ++stage; + /* fallthrough */ + + case ALL_EVASIONS: + while (cur < endMoves) + { + move = pick_best(cur++, endMoves); + if (move != ttMove) + return move; + } + break; + + case PROBCUT_INIT: + cur = moves; + endMoves = generate(pos, cur); + score(); + ++stage; + /* fallthrough */ + + case PROBCUT_CAPTURES: + while (cur < endMoves) + { + move = pick_best(cur++, endMoves); + if ( move != ttMove + && pos.see_ge(move, threshold)) + return move; + } + break; + + case QCAPTURES_1_INIT: case QCAPTURES_2_INIT: + cur = moves; + endMoves = generate(pos, cur); + score(); + ++stage; + /* fallthrough */ + + case QCAPTURES_1: case QCAPTURES_2: + while (cur < endMoves) + { + move = pick_best(cur++, endMoves); + if (move != ttMove) + return move; + } + if (stage == QCAPTURES_2) + break; + cur = moves; + endMoves = generate(pos, cur); + ++stage; + /* fallthrough */ + + case QCHECKS: + while (cur < endMoves) + { + move = cur++->move; + if (move != ttMove) + return move; + } + break; + + case QSEARCH_RECAPTURES: + cur = moves; + endMoves = generate(pos, cur); + score(); + ++stage; + /* fallthrough */ + + case QRECAPTURES: + while (cur < endMoves) + { + move = pick_best(cur++, endMoves); + if (to_sq(move) == recaptureSquare) + return move; + } + break; + + default: + assert(false); + } + + return MOVE_NONE; +} diff --git a/src/movepick.h b/src/movepick.h new file mode 100644 index 0000000..0aba61d --- /dev/null +++ b/src/movepick.h @@ -0,0 +1,151 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef MOVEPICK_H_INCLUDED +#define MOVEPICK_H_INCLUDED + +#include +#include + +#include "movegen.h" +#include "position.h" +#include "types.h" + +/// StatBoards is a generic 2-dimensional array used to store various statistics +template +struct StatBoards : public std::array, Size1> { + + void fill(const T& v) { + T* p = &(*this)[0][0]; + std::fill(p, p + sizeof(*this) / sizeof(*p), v); + } + + void update(T& entry, int bonus, const int D) { + + assert(abs(bonus) <= D); // Ensure range is [-32 * D, 32 * D] + assert(abs(32 * D) < (std::numeric_limits::max)()); // Ensure we don't overflow + + entry += bonus * 32 - entry * abs(bonus) / D; + + assert(abs(entry) <= 32 * D); + } +}; + +/// StatCubes is a generic 3-dimensional array used to store various statistics +template +struct StatCubes : public std::array, Size2>, Size1> { + + void fill(const T& v) { + T* p = &(*this)[0][0][0]; + std::fill(p, p + sizeof(*this) / sizeof(*p), v); + } + + void update(T& entry, int bonus, const int D, const int W) { + + assert(abs(bonus) <= D); // Ensure range is [-W * D, W * D] + assert(abs(W * D) < (std::numeric_limits::max)()); // Ensure we don't overflow + + entry += bonus * W - entry * abs(bonus) / D; + + assert(abs(entry) <= W * D); + } +}; + +/// ButterflyBoards are 2 tables (one for each color) indexed by the move's from +/// and to squares, see chessprogramming.wikispaces.com/Butterfly+Boards +typedef StatBoards ButterflyBoards; + +/// PieceToBoards are addressed by a move's [piece][to] information +typedef StatBoards PieceToBoards; + +/// CapturePieceToBoards are addressed by a move's [piece][to][captured piece type] information +typedef StatCubes CapturePieceToBoards; + +/// ButterflyHistory records how often quiet moves have been successful or +/// unsuccessful during the current search, and is used for reduction and move +/// ordering decisions. It uses ButterflyBoards as backing store. +struct ButterflyHistory : public ButterflyBoards { + + void update(Color c, Move m, int bonus) { + StatBoards::update((*this)[c][from_to(m)], bonus, 324); + } +}; + +/// PieceToHistory is like ButterflyHistory, but is based on PieceToBoards +struct PieceToHistory : public PieceToBoards { + + void update(Piece pc, Square to, int bonus) { + StatBoards::update((*this)[pc][to], bonus, 936); + } +}; + +/// CapturePieceToHistory is like PieceToHistory, but is based on CapturePieceToBoards +struct CapturePieceToHistory : public CapturePieceToBoards { + + void update(Piece pc, Square to, PieceType captured, int bonus) { + StatCubes::update((*this)[pc][to][captured], bonus, 324, 2); + } +}; + +/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous +/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic +typedef StatBoards CounterMoveHistory; + +/// ContinuationHistory is the history of a given pair of moves, usually the +/// current one given a previous one. History table is based on PieceToBoards +/// instead of ButterflyBoards. +typedef StatBoards ContinuationHistory; + + +/// MovePicker class is used to pick one pseudo legal move at a time from the +/// current position. The most important method is next_move(), which returns a +/// new pseudo legal move each time it is called, until there are no moves left, +/// when MOVE_NONE is returned. In order to improve the efficiency of the alpha +/// beta algorithm, MovePicker attempts to return the moves which are most likely +/// to get a cut-off first. + +class MovePicker { +public: + MovePicker(const MovePicker&) = delete; + MovePicker& operator=(const MovePicker&) = delete; + MovePicker(const Position&, Move, Value, const CapturePieceToHistory*); + MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const CapturePieceToHistory*, Square); + MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const CapturePieceToHistory*, const PieceToHistory**, Move, Move*); + Move next_move(bool skipQuiets = false); + +private: + template void score(); + ExtMove* begin() { return cur; } + ExtMove* end() { return endMoves; } + + const Position& pos; + const ButterflyHistory* mainHistory; + const CapturePieceToHistory* captureHistory; + const PieceToHistory** contHistory; + Move ttMove, countermove, killers[2]; + ExtMove *cur, *endMoves, *endBadCaptures; + int stage; + Square recaptureSquare; + Value threshold; + Depth depth; + ExtMove moves[MAX_MOVES]; +}; + +#endif // #ifndef MOVEPICK_H_INCLUDED diff --git a/src/pawns.cpp b/src/pawns.cpp new file mode 100644 index 0000000..ceacca8 --- /dev/null +++ b/src/pawns.cpp @@ -0,0 +1,299 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include + +#include "bitboard.h" +#include "pawns.h" +#include "position.h" +#include "thread.h" + +namespace { + + #define V Value + #define S(mg, eg) make_score(mg, eg) + + // Isolated pawn penalty + const Score Isolated = S(13, 18); + + // Backward pawn penalty + const Score Backward = S(24, 12); + + // Connected pawn bonus by opposed, phalanx, #support and rank + Score Connected[2][2][3][RANK_NB]; + + // Doubled pawn penalty + const Score Doubled = S(18, 38); + + // Weakness of our pawn shelter in front of the king by [isKingFile][distance from edge][rank]. + // RANK_1 = 0 is used for files where we have no pawns or our pawn is behind our king. + const Value ShelterWeakness[][int(FILE_NB) / 2][RANK_NB] = { + { { V( 97), V(17), V( 9), V(44), V( 84), V( 87), V( 99) }, // Not On King file + { V(106), V( 6), V(33), V(86), V( 87), V(104), V(112) }, + { V(101), V( 2), V(65), V(98), V( 58), V( 89), V(115) }, + { V( 73), V( 7), V(54), V(73), V( 84), V( 83), V(111) } }, + { { V(104), V(20), V( 6), V(27), V( 86), V( 93), V( 82) }, // On King file + { V(123), V( 9), V(34), V(96), V(112), V( 88), V( 75) }, + { V(120), V(25), V(65), V(91), V( 66), V( 78), V(117) }, + { V( 81), V( 2), V(47), V(63), V( 94), V( 93), V(104) } } + }; + + // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]. + // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has + // no pawn on the given file, or their pawn is behind our king. + const Value StormDanger[][4][RANK_NB] = { + { { V( 0), V(-290), V(-274), V(57), V(41) }, // BlockedByKing + { V( 0), V( 60), V( 144), V(39), V(13) }, + { V( 0), V( 65), V( 141), V(41), V(34) }, + { V( 0), V( 53), V( 127), V(56), V(14) } }, + { { V( 4), V( 73), V( 132), V(46), V(31) }, // Unopposed + { V( 1), V( 64), V( 143), V(26), V(13) }, + { V( 1), V( 47), V( 110), V(44), V(24) }, + { V( 0), V( 72), V( 127), V(50), V(31) } }, + { { V( 0), V( 0), V( 79), V(23), V( 1) }, // BlockedByPawn + { V( 0), V( 0), V( 148), V(27), V( 2) }, + { V( 0), V( 0), V( 161), V(16), V( 1) }, + { V( 0), V( 0), V( 171), V(22), V(15) } }, + { { V(22), V( 45), V( 104), V(62), V( 6) }, // Unblocked + { V(31), V( 30), V( 99), V(39), V(19) }, + { V(23), V( 29), V( 96), V(41), V(15) }, + { V(21), V( 23), V( 116), V(41), V(15) } } + }; + + // Max bonus for king safety. Corresponds to start position with all the pawns + // in front of the king and no enemy pawn on the horizon. + const Value MaxSafetyBonus = V(258); + + #undef S + #undef V + + template + Score evaluate(const Position& pos, Pawns::Entry* e) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); + const Direction Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST); + const Direction Left = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); + + Bitboard b, neighbours, stoppers, doubled, supported, phalanx; + Bitboard lever, leverPush; + Square s; + bool opposed, backward; + Score score = SCORE_ZERO; + const Square* pl = pos.squares(Us); + + Bitboard ourPawns = pos.pieces( Us, PAWN); + Bitboard theirPawns = pos.pieces(Them, PAWN); + + e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0; + e->semiopenFiles[Us] = 0xFF; + e->kingSquares[Us] = SQ_NONE; + e->pawnAttacks[Us] = shift(ourPawns) | shift(ourPawns); + e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares); + e->pawnsOnSquares[Us][WHITE] = pos.count(Us) - e->pawnsOnSquares[Us][BLACK]; + + // Loop through all pawns of the current color and score each pawn + while ((s = *pl++) != SQ_NONE) + { + assert(pos.piece_on(s) == make_piece(Us, PAWN)); + + File f = file_of(s); + + e->semiopenFiles[Us] &= ~(1 << f); + e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s); + + // Flag the pawn + opposed = theirPawns & forward_file_bb(Us, s); + stoppers = theirPawns & passed_pawn_mask(Us, s); + lever = theirPawns & PawnAttacks[Us][s]; + leverPush = theirPawns & PawnAttacks[Us][s + Up]; + doubled = ourPawns & (s - Up); + neighbours = ourPawns & adjacent_files_bb(f); + phalanx = neighbours & rank_bb(s); + supported = neighbours & rank_bb(s - Up); + + // A pawn is backward when it is behind all pawns of the same color on the + // adjacent files and cannot be safely advanced. + if (!neighbours || lever || relative_rank(Us, s) >= RANK_5) + backward = false; + else + { + // Find the backmost rank with neighbours or stoppers + b = rank_bb(backmost_sq(Us, neighbours | stoppers)); + + // The pawn is backward when it cannot safely progress to that rank: + // either there is a stopper in the way on this rank, or there is a + // stopper on adjacent file which controls the way to that rank. + backward = (b | shift(b & adjacent_files_bb(f))) & stoppers; + + assert(!(backward && (forward_ranks_bb(Them, s + Up) & neighbours))); + } + + // Passed pawns will be properly scored in evaluation because we need + // full attack info to evaluate them. Include also not passed pawns + // which could become passed after one or two pawn pushes when are + // not attacked more times than defended. + if ( !(stoppers ^ lever ^ leverPush) + && !(ourPawns & forward_file_bb(Us, s)) + && popcount(supported) >= popcount(lever) + && popcount(phalanx) >= popcount(leverPush)) + e->passedPawns[Us] |= s; + + else if ( stoppers == SquareBB[s + Up] + && relative_rank(Us, s) >= RANK_5) + { + b = shift(supported) & ~theirPawns; + while (b) + if (!more_than_one(theirPawns & PawnAttacks[Us][pop_lsb(&b)])) + e->passedPawns[Us] |= s; + } + + // Score this pawn + if (supported | phalanx) + score += Connected[opposed][bool(phalanx)][popcount(supported)][relative_rank(Us, s)]; + + else if (!neighbours) + score -= Isolated, e->weakUnopposed[Us] += !opposed; + + else if (backward) + score -= Backward, e->weakUnopposed[Us] += !opposed; + + if (doubled && !supported) + score -= Doubled; + } + + return score; + } + +} // namespace + +namespace Pawns { + +/// Pawns::init() initializes some tables needed by evaluation. Instead of using +/// hard-coded tables, when makes sense, we prefer to calculate them with a formula +/// to reduce independent parameters and to allow easier tuning and better insight. + +void init() { + + static const int Seed[RANK_NB] = { 0, 13, 24, 18, 76, 100, 175, 330 }; + + for (int opposed = 0; opposed <= 1; ++opposed) + for (int phalanx = 0; phalanx <= 1; ++phalanx) + for (int support = 0; support <= 2; ++support) + for (Rank r = RANK_2; r < RANK_8; ++r) + { + int v = 17 * support; + v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed; + + Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4); + } +} + + +/// Pawns::probe() looks up the current position's pawns configuration in +/// the pawns hash table. It returns a pointer to the Entry if the position +/// is found. Otherwise a new Entry is computed and stored there, so we don't +/// have to recompute all when the same pawns configuration occurs again. + +Entry* probe(const Position& pos) { + + Key key = pos.pawn_key(); + Entry* e = pos.this_thread()->pawnsTable[key]; + + if (e->key == key) + return e; + + e->key = key; + e->score = evaluate(pos, e) - evaluate(pos, e); + e->asymmetry = popcount(e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]); + e->openFiles = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]); + return e; +} + + +/// Entry::shelter_storm() calculates shelter and storm penalties for the file +/// the king is on, as well as the two closest files. + +template +Value Entry::shelter_storm(const Position& pos, Square ksq) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + + enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked }; + + Bitboard b = pos.pieces(PAWN) & (forward_ranks_bb(Us, ksq) | rank_bb(ksq)); + Bitboard ourPawns = b & pos.pieces(Us); + Bitboard theirPawns = b & pos.pieces(Them); + Value safety = MaxSafetyBonus; + File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq))); + + for (File f = File(center - 1); f <= File(center + 1); ++f) + { + b = ourPawns & file_bb(f); + Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1; + + b = theirPawns & file_bb(f); + Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; + + int d = std::min(f, ~f); + safety -= ShelterWeakness[f == file_of(ksq)][d][rkUs] + + StormDanger + [f == file_of(ksq) && rkThem == relative_rank(Us, ksq) + 1 ? BlockedByKing : + rkUs == RANK_1 ? Unopposed : + rkThem == rkUs + 1 ? BlockedByPawn : Unblocked] + [d][rkThem]; + } + + return safety; +} + + +/// Entry::do_king_safety() calculates a bonus for king safety. It is called only +/// when king square changes, which is about 20% of total king_safety() calls. + +template +Score Entry::do_king_safety(const Position& pos, Square ksq) { + + kingSquares[Us] = ksq; + castlingRights[Us] = pos.can_castle(Us); + int minKingPawnDistance = 0; + + Bitboard pawns = pos.pieces(Us, PAWN); + if (pawns) + while (!(DistanceRingBB[ksq][minKingPawnDistance++] & pawns)) {} + + Value bonus = shelter_storm(pos, ksq); + + // If we can castle use the bonus after the castling if it is bigger + if (pos.can_castle(MakeCastling::right)) + bonus = std::max(bonus, shelter_storm(pos, relative_square(Us, SQ_G1))); + + if (pos.can_castle(MakeCastling::right)) + bonus = std::max(bonus, shelter_storm(pos, relative_square(Us, SQ_C1))); + + return make_score(bonus, -16 * minKingPawnDistance); +} + +// Explicit template instantiation +template Score Entry::do_king_safety(const Position& pos, Square ksq); +template Score Entry::do_king_safety(const Position& pos, Square ksq); + +} // namespace Pawns diff --git a/src/pawns.h b/src/pawns.h new file mode 100644 index 0000000..a9c21ff --- /dev/null +++ b/src/pawns.h @@ -0,0 +1,90 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef PAWNS_H_INCLUDED +#define PAWNS_H_INCLUDED + +#include "misc.h" +#include "position.h" +#include "types.h" + +namespace Pawns { + +/// Pawns::Entry contains various information about a pawn structure. A lookup +/// to the pawn hash table (performed by calling the probe function) returns a +/// pointer to an Entry object. + +struct Entry { + + Score pawns_score() const { return score; } + Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; } + Bitboard passed_pawns(Color c) const { return passedPawns[c]; } + Bitboard pawn_attacks_span(Color c) const { return pawnAttacksSpan[c]; } + int weak_unopposed(Color c) const { return weakUnopposed[c]; } + int pawn_asymmetry() const { return asymmetry; } + int open_files() const { return openFiles; } + + int semiopen_file(Color c, File f) const { + return semiopenFiles[c] & (1 << f); + } + + int semiopen_side(Color c, File f, bool leftSide) const { + return semiopenFiles[c] & (leftSide ? (1 << f) - 1 : ~((1 << (f + 1)) - 1)); + } + + int pawns_on_same_color_squares(Color c, Square s) const { + return pawnsOnSquares[c][bool(DarkSquares & s)]; + } + + template + Score king_safety(const Position& pos, Square ksq) { + return kingSquares[Us] == ksq && castlingRights[Us] == pos.can_castle(Us) + ? kingSafety[Us] : (kingSafety[Us] = do_king_safety(pos, ksq)); + } + + template + Score do_king_safety(const Position& pos, Square ksq); + + template + Value shelter_storm(const Position& pos, Square ksq); + + Key key; + Score score; + Bitboard passedPawns[COLOR_NB]; + Bitboard pawnAttacks[COLOR_NB]; + Bitboard pawnAttacksSpan[COLOR_NB]; + Square kingSquares[COLOR_NB]; + Score kingSafety[COLOR_NB]; + int weakUnopposed[COLOR_NB]; + int castlingRights[COLOR_NB]; + int semiopenFiles[COLOR_NB]; + int pawnsOnSquares[COLOR_NB][COLOR_NB]; // [color][light/dark squares] + int asymmetry; + int openFiles; +}; + +typedef HashTable Table; + +void init(); +Entry* probe(const Position& pos); + +} // namespace Pawns + +#endif // #ifndef PAWNS_H_INCLUDED diff --git a/src/position.cpp b/src/position.cpp new file mode 100644 index 0000000..7e12fdc --- /dev/null +++ b/src/position.cpp @@ -0,0 +1,1213 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include // For offsetof() +#include // For std::memset, std::memcmp +#include +#include + +#include "bitboard.h" +#include "misc.h" +#include "movegen.h" +#include "position.h" +#include "thread.h" +#include "tt.h" +#include "uci.h" +#include "syzygy/tbprobe.h" + +using std::string; + +namespace PSQT { + extern Score psq[PIECE_NB][SQUARE_NB]; +} + +namespace Zobrist { + + Key psq[PIECE_NB][SQUARE_NB]; + Key enpassant[FILE_NB]; + Key castling[CASTLING_RIGHT_NB]; + Key side, noPawns; +} + +namespace { + +const string PieceToChar(" PNBRQK pnbrqk"); + +const Piece Pieces[] = { W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING, + B_PAWN, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING }; + +// min_attacker() is a helper function used by see_ge() to locate the least +// valuable attacker for the side to move, remove the attacker we just found +// from the bitboards and scan for new X-ray attacks behind it. + +template +PieceType min_attacker(const Bitboard* bb, Square to, Bitboard stmAttackers, + Bitboard& occupied, Bitboard& attackers) { + + Bitboard b = stmAttackers & bb[Pt]; + if (!b) + return min_attacker(bb, to, stmAttackers, occupied, attackers); + + occupied ^= b & ~(b - 1); + + if (Pt == PAWN || Pt == BISHOP || Pt == QUEEN) + attackers |= attacks_bb(to, occupied) & (bb[BISHOP] | bb[QUEEN]); + + if (Pt == ROOK || Pt == QUEEN) + attackers |= attacks_bb(to, occupied) & (bb[ROOK] | bb[QUEEN]); + + attackers &= occupied; // After X-ray that may add already processed pieces + return (PieceType)Pt; +} + +template<> +PieceType min_attacker(const Bitboard*, Square, Bitboard, Bitboard&, Bitboard&) { + return KING; // No need to update bitboards: it is the last cycle +} + +} // namespace + + +/// operator<<(Position) returns an ASCII representation of the position + +std::ostream& operator<<(std::ostream& os, const Position& pos) { + + os << "\n +---+---+---+---+---+---+---+---+\n"; + + for (Rank r = RANK_8; r >= RANK_1; --r) + { + for (File f = FILE_A; f <= FILE_H; ++f) + os << " | " << PieceToChar[pos.piece_on(make_square(f, r))]; + + os << " |\n +---+---+---+---+---+---+---+---+\n"; + } + + os << "\nFen: " << pos.fen() << "\nKey: " << std::hex << std::uppercase + << std::setfill('0') << std::setw(16) << pos.key() + << std::setfill(' ') << std::dec << "\nCheckers: "; + + for (Bitboard b = pos.checkers(); b; ) + os << UCI::square(pop_lsb(&b)) << " "; + + if ( int(Tablebases::MaxCardinality) >= popcount(pos.pieces()) + && !pos.can_castle(ANY_CASTLING)) + { + StateInfo st; + Position p; + p.set(pos.fen(), pos.is_chess960(), &st, pos.this_thread()); + Tablebases::ProbeState s1, s2; + Tablebases::WDLScore wdl = Tablebases::probe_wdl(p, &s1); + int dtz = Tablebases::probe_dtz(p, &s2); + os << "\nTablebases WDL: " << std::setw(4) << wdl << " (" << s1 << ")" + << "\nTablebases DTZ: " << std::setw(4) << dtz << " (" << s2 << ")"; + } + + return os; +} + + +/// Position::init() initializes at startup the various arrays used to compute +/// hash keys. + +void Position::init() { + + PRNG rng(1070372); + + for (Piece pc : Pieces) + for (Square s = SQ_A1; s <= SQ_H8; ++s) + Zobrist::psq[pc][s] = rng.rand(); + + for (File f = FILE_A; f <= FILE_H; ++f) + Zobrist::enpassant[f] = rng.rand(); + + for (int cr = NO_CASTLING; cr <= ANY_CASTLING; ++cr) + { + Zobrist::castling[cr] = 0; + Bitboard b = cr; + while (b) + { + Key k = Zobrist::castling[1ULL << pop_lsb(&b)]; + Zobrist::castling[cr] ^= k ? k : rng.rand(); + } + } + + Zobrist::side = rng.rand(); + Zobrist::noPawns = rng.rand(); +} + + +/// Position::set() initializes the position object with the given FEN string. +/// This function is not very robust - make sure that input FENs are correct, +/// this is assumed to be the responsibility of the GUI. + +Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Thread* th) { +/* + A FEN string defines a particular position using only the ASCII character set. + + A FEN string contains six fields separated by a space. The fields are: + + 1) Piece placement (from white's perspective). Each rank is described, starting + with rank 8 and ending with rank 1. Within each rank, the contents of each + square are described from file A through file H. Following the Standard + Algebraic Notation (SAN), each piece is identified by a single letter taken + from the standard English names. White pieces are designated using upper-case + letters ("PNBRQK") whilst Black uses lowercase ("pnbrqk"). Blank squares are + noted using digits 1 through 8 (the number of blank squares), and "/" + separates ranks. + + 2) Active color. "w" means white moves next, "b" means black. + + 3) Castling availability. If neither side can castle, this is "-". Otherwise, + this has one or more letters: "K" (White can castle kingside), "Q" (White + can castle queenside), "k" (Black can castle kingside), and/or "q" (Black + can castle queenside). + + 4) En passant target square (in algebraic notation). If there's no en passant + target square, this is "-". If a pawn has just made a 2-square move, this + is the position "behind" the pawn. This is recorded only if there is a pawn + in position to make an en passant capture, and if there really is a pawn + that might have advanced two squares. + + 5) Halfmove clock. This is the number of halfmoves since the last pawn advance + or capture. This is used to determine if a draw can be claimed under the + fifty-move rule. + + 6) Fullmove number. The number of the full move. It starts at 1, and is + incremented after Black's move. +*/ + + unsigned char col, row, token; + size_t idx; + Square sq = SQ_A8; + std::istringstream ss(fenStr); + + std::memset(this, 0, sizeof(Position)); + std::memset(si, 0, sizeof(StateInfo)); + std::fill_n(&pieceList[0][0], sizeof(pieceList) / sizeof(Square), SQ_NONE); + st = si; + + ss >> std::noskipws; + + // 1. Piece placement + while ((ss >> token) && !isspace(token)) + { + if (isdigit(token)) + sq += (token - '0') * EAST; // Advance the given number of files + + else if (token == '/') + sq += 2 * SOUTH; + + else if ((idx = PieceToChar.find(token)) != string::npos) + { + put_piece(Piece(idx), sq); + ++sq; + } + } + + // 2. Active color + ss >> token; + sideToMove = (token == 'w' ? WHITE : BLACK); + ss >> token; + + // 3. Castling availability. Compatible with 3 standards: Normal FEN standard, + // Shredder-FEN that uses the letters of the columns on which the rooks began + // the game instead of KQkq and also X-FEN standard that, in case of Chess960, + // if an inner rook is associated with the castling right, the castling tag is + // replaced by the file letter of the involved rook, as for the Shredder-FEN. + while ((ss >> token) && !isspace(token)) + { + Square rsq; + Color c = islower(token) ? BLACK : WHITE; + Piece rook = make_piece(c, ROOK); + + token = char(toupper(token)); + + if (token == 'K') + for (rsq = relative_square(c, SQ_H1); piece_on(rsq) != rook; --rsq) {} + + else if (token == 'Q') + for (rsq = relative_square(c, SQ_A1); piece_on(rsq) != rook; ++rsq) {} + + else if (token >= 'A' && token <= 'H') + rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); + + else + continue; + + set_castling_right(c, rsq); + } + + // 4. En passant square. Ignore if no pawn capture is possible + if ( ((ss >> col) && (col >= 'a' && col <= 'h')) + && ((ss >> row) && (row == '3' || row == '6'))) + { + st->epSquare = make_square(File(col - 'a'), Rank(row - '1')); + + if ( !(attackers_to(st->epSquare) & pieces(sideToMove, PAWN)) + || !(pieces(~sideToMove, PAWN) & (st->epSquare + pawn_push(~sideToMove)))) + st->epSquare = SQ_NONE; + } + else + st->epSquare = SQ_NONE; + + // 5-6. Halfmove clock and fullmove number + ss >> std::skipws >> st->rule50 >> gamePly; + + // Convert from fullmove starting from 1 to gamePly starting from 0, + // handle also common incorrect FEN with fullmove = 0. + gamePly = std::max(2 * (gamePly - 1), 0) + (sideToMove == BLACK); + + chess960 = isChess960; + thisThread = th; + set_state(st); + + assert(pos_is_ok()); + + return *this; +} + + +/// Position::set_castling_right() is a helper function used to set castling +/// rights given the corresponding color and the rook starting square. + +void Position::set_castling_right(Color c, Square rfrom) { + + Square kfrom = square(c); + CastlingSide cs = kfrom < rfrom ? KING_SIDE : QUEEN_SIDE; + CastlingRight cr = (c | cs); + + st->castlingRights |= cr; + castlingRightsMask[kfrom] |= cr; + castlingRightsMask[rfrom] |= cr; + castlingRookSquare[cr] = rfrom; + + Square kto = relative_square(c, cs == KING_SIDE ? SQ_G1 : SQ_C1); + Square rto = relative_square(c, cs == KING_SIDE ? SQ_F1 : SQ_D1); + + for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); ++s) + if (s != kfrom && s != rfrom) + castlingPath[cr] |= s; + + for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); ++s) + if (s != kfrom && s != rfrom) + castlingPath[cr] |= s; +} + + +/// Position::set_check_info() sets king attacks to detect if a move gives check + +void Position::set_check_info(StateInfo* si) const { + + si->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square(WHITE), si->pinnersForKing[WHITE]); + si->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square(BLACK), si->pinnersForKing[BLACK]); + + Square ksq = square(~sideToMove); + + si->checkSquares[PAWN] = attacks_from(ksq, ~sideToMove); + si->checkSquares[KNIGHT] = attacks_from(ksq); + si->checkSquares[BISHOP] = attacks_from(ksq); + si->checkSquares[ROOK] = attacks_from(ksq); + si->checkSquares[QUEEN] = si->checkSquares[BISHOP] | si->checkSquares[ROOK]; + si->checkSquares[KING] = 0; +} + + +/// Position::set_state() computes the hash keys of the position, and other +/// data that once computed is updated incrementally as moves are made. +/// The function is only used when a new position is set up, and to verify +/// the correctness of the StateInfo data when running in debug mode. + +void Position::set_state(StateInfo* si) const { + + si->key = si->materialKey = 0; + si->pawnKey = Zobrist::noPawns; + si->nonPawnMaterial[WHITE] = si->nonPawnMaterial[BLACK] = VALUE_ZERO; + si->psq = SCORE_ZERO; + si->checkersBB = attackers_to(square(sideToMove)) & pieces(~sideToMove); + + set_check_info(si); + + for (Bitboard b = pieces(); b; ) + { + Square s = pop_lsb(&b); + Piece pc = piece_on(s); + si->key ^= Zobrist::psq[pc][s]; + si->psq += PSQT::psq[pc][s]; + } + + if (si->epSquare != SQ_NONE) + si->key ^= Zobrist::enpassant[file_of(si->epSquare)]; + + if (sideToMove == BLACK) + si->key ^= Zobrist::side; + + si->key ^= Zobrist::castling[si->castlingRights]; + + for (Bitboard b = pieces(PAWN); b; ) + { + Square s = pop_lsb(&b); + si->pawnKey ^= Zobrist::psq[piece_on(s)][s]; + } + + for (Piece pc : Pieces) + { + if (type_of(pc) != PAWN && type_of(pc) != KING) + si->nonPawnMaterial[color_of(pc)] += pieceCount[pc] * PieceValue[MG][pc]; + + for (int cnt = 0; cnt < pieceCount[pc]; ++cnt) + si->materialKey ^= Zobrist::psq[pc][cnt]; + } +} + + +/// Position::set() is an overload to initialize the position object with +/// the given endgame code string like "KBPKN". It is mainly a helper to +/// get the material key out of an endgame code. + +Position& Position::set(const string& code, Color c, StateInfo* si) { + + assert(code.length() > 0 && code.length() < 8); + assert(code[0] == 'K'); + + string sides[] = { code.substr(code.find('K', 1)), // Weak + code.substr(0, code.find('K', 1)) }; // Strong + + std::transform(sides[c].begin(), sides[c].end(), sides[c].begin(), tolower); + + string fenStr = "8/" + sides[0] + char(8 - sides[0].length() + '0') + "/8/8/8/8/" + + sides[1] + char(8 - sides[1].length() + '0') + "/8 w - - 0 10"; + + return set(fenStr, false, si, nullptr); +} + + +/// Position::fen() returns a FEN representation of the position. In case of +/// Chess960 the Shredder-FEN notation is used. This is mainly a debugging function. + +const string Position::fen() const { + + int emptyCnt; + std::ostringstream ss; + + for (Rank r = RANK_8; r >= RANK_1; --r) + { + for (File f = FILE_A; f <= FILE_H; ++f) + { + for (emptyCnt = 0; f <= FILE_H && empty(make_square(f, r)); ++f) + ++emptyCnt; + + if (emptyCnt) + ss << emptyCnt; + + if (f <= FILE_H) + ss << PieceToChar[piece_on(make_square(f, r))]; + } + + if (r > RANK_1) + ss << '/'; + } + + ss << (sideToMove == WHITE ? " w " : " b "); + + if (can_castle(WHITE_OO)) + ss << (chess960 ? char('A' + file_of(castling_rook_square(WHITE | KING_SIDE))) : 'K'); + + if (can_castle(WHITE_OOO)) + ss << (chess960 ? char('A' + file_of(castling_rook_square(WHITE | QUEEN_SIDE))) : 'Q'); + + if (can_castle(BLACK_OO)) + ss << (chess960 ? char('a' + file_of(castling_rook_square(BLACK | KING_SIDE))) : 'k'); + + if (can_castle(BLACK_OOO)) + ss << (chess960 ? char('a' + file_of(castling_rook_square(BLACK | QUEEN_SIDE))) : 'q'); + + if (!can_castle(WHITE) && !can_castle(BLACK)) + ss << '-'; + + ss << (ep_square() == SQ_NONE ? " - " : " " + UCI::square(ep_square()) + " ") + << st->rule50 << " " << 1 + (gamePly - (sideToMove == BLACK)) / 2; + + return ss.str(); +} + + +/// Position::slider_blockers() returns a bitboard of all the pieces (both colors) +/// that are blocking attacks on the square 's' from 'sliders'. A piece blocks a +/// slider if removing that piece from the board would result in a position where +/// square 's' is attacked. For example, a king-attack blocking piece can be either +/// a pinned or a discovered check piece, according if its color is the opposite +/// or the same of the color of the slider. + +Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const { + + Bitboard result = 0; + pinners = 0; + + // Snipers are sliders that attack 's' when a piece is removed + Bitboard snipers = ( (PseudoAttacks[ ROOK][s] & pieces(QUEEN, ROOK)) + | (PseudoAttacks[BISHOP][s] & pieces(QUEEN, BISHOP))) & sliders; + + while (snipers) + { + Square sniperSq = pop_lsb(&snipers); + Bitboard b = between_bb(s, sniperSq) & pieces(); + + if (!more_than_one(b)) + { + result |= b; + if (b & pieces(color_of(piece_on(s)))) + pinners |= sniperSq; + } + } + return result; +} + + +/// Position::attackers_to() computes a bitboard of all pieces which attack a +/// given square. Slider attacks use the occupied bitboard to indicate occupancy. + +Bitboard Position::attackers_to(Square s, Bitboard occupied) const { + + return (attacks_from(s, BLACK) & pieces(WHITE, PAWN)) + | (attacks_from(s, WHITE) & pieces(BLACK, PAWN)) + | (attacks_from(s) & pieces(KNIGHT)) + | (attacks_bb< ROOK>(s, occupied) & pieces( ROOK, QUEEN)) + | (attacks_bb(s, occupied) & pieces(BISHOP, QUEEN)) + | (attacks_from(s) & pieces(KING)); +} + + +/// Position::legal() tests whether a pseudo-legal move is legal + +bool Position::legal(Move m) const { + + assert(is_ok(m)); + + Color us = sideToMove; + Square from = from_sq(m); + + assert(color_of(moved_piece(m)) == us); + assert(piece_on(square(us)) == make_piece(us, KING)); + + // En passant captures are a tricky special case. Because they are rather + // uncommon, we do it simply by testing whether the king is attacked after + // the move is made. + if (type_of(m) == ENPASSANT) + { + Square ksq = square(us); + Square to = to_sq(m); + Square capsq = to - pawn_push(us); + Bitboard occupied = (pieces() ^ from ^ capsq) | to; + + assert(to == ep_square()); + assert(moved_piece(m) == make_piece(us, PAWN)); + assert(piece_on(capsq) == make_piece(~us, PAWN)); + assert(piece_on(to) == NO_PIECE); + + return !(attacks_bb< ROOK>(ksq, occupied) & pieces(~us, QUEEN, ROOK)) + && !(attacks_bb(ksq, occupied) & pieces(~us, QUEEN, BISHOP)); + } + + // If the moving piece is a king, check whether the destination + // square is attacked by the opponent. Castling moves are checked + // for legality during move generation. + if (type_of(piece_on(from)) == KING) + return type_of(m) == CASTLING || !(attackers_to(to_sq(m)) & pieces(~us)); + + // A non-king move is legal if and only if it is not pinned or it + // is moving along the ray towards or away from the king. + return !(pinned_pieces(us) & from) + || aligned(from, to_sq(m), square(us)); +} + + +/// Position::pseudo_legal() takes a random move and tests whether the move is +/// pseudo legal. It is used to validate moves from TT that can be corrupted +/// due to SMP concurrent access or hash position key aliasing. + +bool Position::pseudo_legal(const Move m) const { + + Color us = sideToMove; + Square from = from_sq(m); + Square to = to_sq(m); + Piece pc = moved_piece(m); + + // Use a slower but simpler function for uncommon cases + if (type_of(m) != NORMAL) + return MoveList(*this).contains(m); + + // Is not a promotion, so promotion piece must be empty + if (promotion_type(m) - KNIGHT != NO_PIECE_TYPE) + return false; + + // If the 'from' square is not occupied by a piece belonging to the side to + // move, the move is obviously not legal. + if (pc == NO_PIECE || color_of(pc) != us) + return false; + + // The destination square cannot be occupied by a friendly piece + if (pieces(us) & to) + return false; + + // Handle the special case of a pawn move + if (type_of(pc) == PAWN) + { + // We have already handled promotion moves, so destination + // cannot be on the 8th/1st rank. + if (rank_of(to) == relative_rank(us, RANK_8)) + return false; + + if ( !(attacks_from(from, us) & pieces(~us) & to) // Not a capture + && !((from + pawn_push(us) == to) && empty(to)) // Not a single push + && !( (from + 2 * pawn_push(us) == to) // Not a double push + && (rank_of(from) == relative_rank(us, RANK_2)) + && empty(to) + && empty(to - pawn_push(us)))) + return false; + } + else if (!(attacks_from(type_of(pc), from) & to)) + return false; + + // Evasions generator already takes care to avoid some kind of illegal moves + // and legal() relies on this. We therefore have to take care that the same + // kind of moves are filtered out here. + if (checkers()) + { + if (type_of(pc) != KING) + { + // Double check? In this case a king move is required + if (more_than_one(checkers())) + return false; + + // Our move must be a blocking evasion or a capture of the checking piece + if (!((between_bb(lsb(checkers()), square(us)) | checkers()) & to)) + return false; + } + // In case of king moves under check we have to remove king so as to catch + // invalid moves like b1a1 when opposite queen is on c1. + else if (attackers_to(to, pieces() ^ from) & pieces(~us)) + return false; + } + + return true; +} + + +/// Position::gives_check() tests whether a pseudo-legal move gives a check + +bool Position::gives_check(Move m) const { + + assert(is_ok(m)); + assert(color_of(moved_piece(m)) == sideToMove); + + Square from = from_sq(m); + Square to = to_sq(m); + + // Is there a direct check? + if (st->checkSquares[type_of(piece_on(from))] & to) + return true; + + // Is there a discovered check? + if ( (discovered_check_candidates() & from) + && !aligned(from, to, square(~sideToMove))) + return true; + + switch (type_of(m)) + { + case NORMAL: + return false; + + case PROMOTION: + return attacks_bb(promotion_type(m), to, pieces() ^ from) & square(~sideToMove); + + // En passant capture with check? We have already handled the case + // of direct checks and ordinary discovered check, so the only case we + // need to handle is the unusual case of a discovered check through + // the captured pawn. + case ENPASSANT: + { + Square capsq = make_square(file_of(to), rank_of(from)); + Bitboard b = (pieces() ^ from ^ capsq) | to; + + return (attacks_bb< ROOK>(square(~sideToMove), b) & pieces(sideToMove, QUEEN, ROOK)) + | (attacks_bb(square(~sideToMove), b) & pieces(sideToMove, QUEEN, BISHOP)); + } + case CASTLING: + { + Square kfrom = from; + Square rfrom = to; // Castling is encoded as 'King captures the rook' + Square kto = relative_square(sideToMove, rfrom > kfrom ? SQ_G1 : SQ_C1); + Square rto = relative_square(sideToMove, rfrom > kfrom ? SQ_F1 : SQ_D1); + + return (PseudoAttacks[ROOK][rto] & square(~sideToMove)) + && (attacks_bb(rto, (pieces() ^ kfrom ^ rfrom) | rto | kto) & square(~sideToMove)); + } + default: + assert(false); + return false; + } +} + + +/// Position::do_move() makes a move, and saves all information necessary +/// to a StateInfo object. The move is assumed to be legal. Pseudo-legal +/// moves should be filtered out before this function is called. + +void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { + + assert(is_ok(m)); + assert(&newSt != st); + + thisThread->nodes.fetch_add(1, std::memory_order_relaxed); + Key k = st->key ^ Zobrist::side; + + // Copy some fields of the old state to our new StateInfo object except the + // ones which are going to be recalculated from scratch anyway and then switch + // our state pointer to point to the new (ready to be updated) state. + std::memcpy(&newSt, st, offsetof(StateInfo, key)); + newSt.previous = st; + st = &newSt; + + // Increment ply counters. In particular, rule50 will be reset to zero later on + // in case of a capture or a pawn move. + ++gamePly; + ++st->rule50; + ++st->pliesFromNull; + + Color us = sideToMove; + Color them = ~us; + Square from = from_sq(m); + Square to = to_sq(m); + Piece pc = piece_on(from); + Piece captured = type_of(m) == ENPASSANT ? make_piece(them, PAWN) : piece_on(to); + + assert(color_of(pc) == us); + assert(captured == NO_PIECE || color_of(captured) == (type_of(m) != CASTLING ? them : us)); + assert(type_of(captured) != KING); + + if (type_of(m) == CASTLING) + { + assert(pc == make_piece(us, KING)); + assert(captured == make_piece(us, ROOK)); + + Square rfrom, rto; + do_castling(us, from, to, rfrom, rto); + + st->psq += PSQT::psq[captured][rto] - PSQT::psq[captured][rfrom]; + k ^= Zobrist::psq[captured][rfrom] ^ Zobrist::psq[captured][rto]; + captured = NO_PIECE; + } + + if (captured) + { + Square capsq = to; + + // If the captured piece is a pawn, update pawn hash key, otherwise + // update non-pawn material. + if (type_of(captured) == PAWN) + { + if (type_of(m) == ENPASSANT) + { + capsq -= pawn_push(us); + + assert(pc == make_piece(us, PAWN)); + assert(to == st->epSquare); + assert(relative_rank(us, to) == RANK_6); + assert(piece_on(to) == NO_PIECE); + assert(piece_on(capsq) == make_piece(them, PAWN)); + + board[capsq] = NO_PIECE; // Not done by remove_piece() + } + + st->pawnKey ^= Zobrist::psq[captured][capsq]; + } + else + st->nonPawnMaterial[them] -= PieceValue[MG][captured]; + + // Update board and piece lists + remove_piece(captured, capsq); + + // Update material hash key and prefetch access to materialTable + k ^= Zobrist::psq[captured][capsq]; + st->materialKey ^= Zobrist::psq[captured][pieceCount[captured]]; + prefetch(thisThread->materialTable[st->materialKey]); + + // Update incremental scores + st->psq -= PSQT::psq[captured][capsq]; + + // Reset rule 50 counter + st->rule50 = 0; + } + + // Update hash key + k ^= Zobrist::psq[pc][from] ^ Zobrist::psq[pc][to]; + + // Reset en passant square + if (st->epSquare != SQ_NONE) + { + k ^= Zobrist::enpassant[file_of(st->epSquare)]; + st->epSquare = SQ_NONE; + } + + // Update castling rights if needed + if (st->castlingRights && (castlingRightsMask[from] | castlingRightsMask[to])) + { + int cr = castlingRightsMask[from] | castlingRightsMask[to]; + k ^= Zobrist::castling[st->castlingRights & cr]; + st->castlingRights &= ~cr; + } + + // Move the piece. The tricky Chess960 castling is handled earlier + if (type_of(m) != CASTLING) + move_piece(pc, from, to); + + // If the moving piece is a pawn do some special extra work + if (type_of(pc) == PAWN) + { + // Set en-passant square if the moved pawn can be captured + if ( (int(to) ^ int(from)) == 16 + && (attacks_from(to - pawn_push(us), us) & pieces(them, PAWN))) + { + st->epSquare = to - pawn_push(us); + k ^= Zobrist::enpassant[file_of(st->epSquare)]; + } + + else if (type_of(m) == PROMOTION) + { + Piece promotion = make_piece(us, promotion_type(m)); + + assert(relative_rank(us, to) == RANK_8); + assert(type_of(promotion) >= KNIGHT && type_of(promotion) <= QUEEN); + + remove_piece(pc, to); + put_piece(promotion, to); + + // Update hash keys + k ^= Zobrist::psq[pc][to] ^ Zobrist::psq[promotion][to]; + st->pawnKey ^= Zobrist::psq[pc][to]; + st->materialKey ^= Zobrist::psq[promotion][pieceCount[promotion]-1] + ^ Zobrist::psq[pc][pieceCount[pc]]; + + // Update incremental score + st->psq += PSQT::psq[promotion][to] - PSQT::psq[pc][to]; + + // Update material + st->nonPawnMaterial[us] += PieceValue[MG][promotion]; + } + + // Update pawn hash key and prefetch access to pawnsTable + st->pawnKey ^= Zobrist::psq[pc][from] ^ Zobrist::psq[pc][to]; + prefetch2(thisThread->pawnsTable[st->pawnKey]); + + // Reset rule 50 draw counter + st->rule50 = 0; + } + + // Update incremental scores + st->psq += PSQT::psq[pc][to] - PSQT::psq[pc][from]; + + // Set capture piece + st->capturedPiece = captured; + + // Update the key with the final value + st->key = k; + + // Calculate checkers bitboard (if move gives check) + st->checkersBB = givesCheck ? attackers_to(square(them)) & pieces(us) : 0; + + sideToMove = ~sideToMove; + + // Update king attacks used for fast check detection + set_check_info(st); + + assert(pos_is_ok()); +} + + +/// Position::undo_move() unmakes a move. When it returns, the position should +/// be restored to exactly the same state as before the move was made. + +void Position::undo_move(Move m) { + + assert(is_ok(m)); + + sideToMove = ~sideToMove; + + Color us = sideToMove; + Square from = from_sq(m); + Square to = to_sq(m); + Piece pc = piece_on(to); + + assert(empty(from) || type_of(m) == CASTLING); + assert(type_of(st->capturedPiece) != KING); + + if (type_of(m) == PROMOTION) + { + assert(relative_rank(us, to) == RANK_8); + assert(type_of(pc) == promotion_type(m)); + assert(type_of(pc) >= KNIGHT && type_of(pc) <= QUEEN); + + remove_piece(pc, to); + pc = make_piece(us, PAWN); + put_piece(pc, to); + } + + if (type_of(m) == CASTLING) + { + Square rfrom, rto; + do_castling(us, from, to, rfrom, rto); + } + else + { + move_piece(pc, to, from); // Put the piece back at the source square + + if (st->capturedPiece) + { + Square capsq = to; + + if (type_of(m) == ENPASSANT) + { + capsq -= pawn_push(us); + + assert(type_of(pc) == PAWN); + assert(to == st->previous->epSquare); + assert(relative_rank(us, to) == RANK_6); + assert(piece_on(capsq) == NO_PIECE); + assert(st->capturedPiece == make_piece(~us, PAWN)); + } + + put_piece(st->capturedPiece, capsq); // Restore the captured piece + } + } + + // Finally point our state pointer back to the previous state + st = st->previous; + --gamePly; + + assert(pos_is_ok()); +} + + +/// Position::do_castling() is a helper used to do/undo a castling move. This +/// is a bit tricky in Chess960 where from/to squares can overlap. +template +void Position::do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto) { + + bool kingSide = to > from; + rfrom = to; // Castling is encoded as "king captures friendly rook" + rto = relative_square(us, kingSide ? SQ_F1 : SQ_D1); + to = relative_square(us, kingSide ? SQ_G1 : SQ_C1); + + // Remove both pieces first since squares could overlap in Chess960 + remove_piece(make_piece(us, KING), Do ? from : to); + remove_piece(make_piece(us, ROOK), Do ? rfrom : rto); + board[Do ? from : to] = board[Do ? rfrom : rto] = NO_PIECE; // Since remove_piece doesn't do it for us + put_piece(make_piece(us, KING), Do ? to : from); + put_piece(make_piece(us, ROOK), Do ? rto : rfrom); +} + + +/// Position::do(undo)_null_move() is used to do(undo) a "null move": It flips +/// the side to move without executing any move on the board. + +void Position::do_null_move(StateInfo& newSt) { + + assert(!checkers()); + assert(&newSt != st); + + std::memcpy(&newSt, st, sizeof(StateInfo)); + newSt.previous = st; + st = &newSt; + + if (st->epSquare != SQ_NONE) + { + st->key ^= Zobrist::enpassant[file_of(st->epSquare)]; + st->epSquare = SQ_NONE; + } + + st->key ^= Zobrist::side; + prefetch(TT.first_entry(st->key)); + + ++st->rule50; + st->pliesFromNull = 0; + + sideToMove = ~sideToMove; + + set_check_info(st); + + assert(pos_is_ok()); +} + +void Position::undo_null_move() { + + assert(!checkers()); + + st = st->previous; + sideToMove = ~sideToMove; +} + + +/// Position::key_after() computes the new hash key after the given move. Needed +/// for speculative prefetch. It doesn't recognize special moves like castling, +/// en-passant and promotions. + +Key Position::key_after(Move m) const { + + Square from = from_sq(m); + Square to = to_sq(m); + Piece pc = piece_on(from); + Piece captured = piece_on(to); + Key k = st->key ^ Zobrist::side; + + if (captured) + k ^= Zobrist::psq[captured][to]; + + return k ^ Zobrist::psq[pc][to] ^ Zobrist::psq[pc][from]; +} + + +/// Position::see_ge (Static Exchange Evaluation Greater or Equal) tests if the +/// SEE value of move is greater or equal to the given threshold. We'll use an +/// algorithm similar to alpha-beta pruning with a null window. + +bool Position::see_ge(Move m, Value threshold) const { + + assert(is_ok(m)); + + // Only deal with normal moves, assume others pass a simple see + if (type_of(m) != NORMAL) + return VALUE_ZERO >= threshold; + + Square from = from_sq(m), to = to_sq(m); + PieceType nextVictim = type_of(piece_on(from)); + Color stm = ~color_of(piece_on(from)); // First consider opponent's move + Value balance; // Values of the pieces taken by us minus opponent's ones + Bitboard occupied, stmAttackers; + + // The opponent may be able to recapture so this is the best result + // we can hope for. + balance = PieceValue[MG][piece_on(to)] - threshold; + + if (balance < VALUE_ZERO) + return false; + + // Now assume the worst possible result: that the opponent can + // capture our piece for free. + balance -= PieceValue[MG][nextVictim]; + + if (balance >= VALUE_ZERO) // Always true if nextVictim == KING + return true; + + bool opponentToMove = true; + occupied = pieces() ^ from ^ to; + + // Find all attackers to the destination square, with the moving piece removed, + // but possibly an X-ray attacker added behind it. + Bitboard attackers = attackers_to(to, occupied) & occupied; + + while (true) + { + // The balance is negative only because we assumed we could win + // the last piece for free. We are truly winning only if we can + // win the last piece _cheaply enough_. Test if we can actually + // do this otherwise "give up". + assert(balance < VALUE_ZERO); + + stmAttackers = attackers & pieces(stm); + + // Don't allow pinned pieces to attack pieces except the king as long all + // pinners are on their original square. + if (!(st->pinnersForKing[stm] & ~occupied)) + stmAttackers &= ~st->blockersForKing[stm]; + + // If we have no more attackers we must give up + if (!stmAttackers) + break; + + // Locate and remove the next least valuable attacker + nextVictim = min_attacker(byTypeBB, to, stmAttackers, occupied, attackers); + + if (nextVictim == KING) + { + // Our only attacker is the king. If the opponent still has + // attackers we must give up. Otherwise we make the move and + // (having no more attackers) the opponent must give up. + if (!(attackers & pieces(~stm))) + opponentToMove = !opponentToMove; + break; + } + + // Assume the opponent can win the next piece for free and switch sides + balance += PieceValue[MG][nextVictim]; + opponentToMove = !opponentToMove; + + // If balance is negative after receiving a free piece then give up + if (balance < VALUE_ZERO) + break; + + // Complete the process of switching sides. The first line swaps + // all negative numbers with non-negative numbers. The compiler + // probably knows that it is just the bitwise negation ~balance. + balance = -balance-1; + stm = ~stm; + } + + // If the opponent gave up we win, otherwise we lose. + return opponentToMove; +} + + +/// Position::is_draw() tests whether the position is drawn by 50-move rule +/// or by repetition. It does not detect stalemates. + +bool Position::is_draw(int ply) const { + + if (st->rule50 > 99 && (!checkers() || MoveList(*this).size())) + return true; + + int end = std::min(st->rule50, st->pliesFromNull); + + if (end < 4) + return false; + + StateInfo* stp = st->previous->previous; + int cnt = 0; + + for (int i = 4; i <= end; i += 2) + { + stp = stp->previous->previous; + + // Return a draw score if a position repeats once earlier but strictly + // after the root, or repeats twice before or at the root. + if ( stp->key == st->key + && ++cnt + (ply > i) == 2) + return true; + } + + return false; +} + + +/// Position::flip() flips position with the white and black sides reversed. This +/// is only useful for debugging e.g. for finding evaluation symmetry bugs. + +void Position::flip() { + + string f, token; + std::stringstream ss(fen()); + + for (Rank r = RANK_8; r >= RANK_1; --r) // Piece placement + { + std::getline(ss, token, r > RANK_1 ? '/' : ' '); + f.insert(0, token + (f.empty() ? " " : "/")); + } + + ss >> token; // Active color + f += (token == "w" ? "B " : "W "); // Will be lowercased later + + ss >> token; // Castling availability + f += token + " "; + + std::transform(f.begin(), f.end(), f.begin(), + [](char c) { return char(islower(c) ? toupper(c) : tolower(c)); }); + + ss >> token; // En passant square + f += (token == "-" ? token : token.replace(1, 1, token[1] == '3' ? "6" : "3")); + + std::getline(ss, token); // Half and full moves + f += token; + + set(f, is_chess960(), st, this_thread()); + + assert(pos_is_ok()); +} + + +/// Position::pos_is_ok() performs some consistency checks for the +/// position object and raises an asserts if something wrong is detected. +/// This is meant to be helpful when debugging. + +bool Position::pos_is_ok() const { + + const bool Fast = true; // Quick (default) or full check? + + if ( (sideToMove != WHITE && sideToMove != BLACK) + || piece_on(square(WHITE)) != W_KING + || piece_on(square(BLACK)) != B_KING + || ( ep_square() != SQ_NONE + && relative_rank(sideToMove, ep_square()) != RANK_6)) + assert(0 && "pos_is_ok: Default"); + + if (Fast) + return true; + + if ( pieceCount[W_KING] != 1 + || pieceCount[B_KING] != 1 + || attackers_to(square(~sideToMove)) & pieces(sideToMove)) + assert(0 && "pos_is_ok: Kings"); + + if ( (pieces(PAWN) & (Rank1BB | Rank8BB)) + || pieceCount[W_PAWN] > 8 + || pieceCount[B_PAWN] > 8) + assert(0 && "pos_is_ok: Pawns"); + + if ( (pieces(WHITE) & pieces(BLACK)) + || (pieces(WHITE) | pieces(BLACK)) != pieces() + || popcount(pieces(WHITE)) > 16 + || popcount(pieces(BLACK)) > 16) + assert(0 && "pos_is_ok: Bitboards"); + + for (PieceType p1 = PAWN; p1 <= KING; ++p1) + for (PieceType p2 = PAWN; p2 <= KING; ++p2) + if (p1 != p2 && (pieces(p1) & pieces(p2))) + assert(0 && "pos_is_ok: Bitboards"); + + StateInfo si = *st; + set_state(&si); + if (std::memcmp(&si, st, sizeof(StateInfo))) + assert(0 && "pos_is_ok: State"); + + for (Piece pc : Pieces) + { + if ( pieceCount[pc] != popcount(pieces(color_of(pc), type_of(pc))) + || pieceCount[pc] != std::count(board, board + SQUARE_NB, pc)) + assert(0 && "pos_is_ok: Pieces"); + + for (int i = 0; i < pieceCount[pc]; ++i) + if (board[pieceList[pc][i]] != pc || index[pieceList[pc][i]] != i) + assert(0 && "pos_is_ok: Index"); + } + + for (Color c = WHITE; c <= BLACK; ++c) + for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1)) + { + if (!can_castle(c | s)) + continue; + + if ( piece_on(castlingRookSquare[c | s]) != make_piece(c, ROOK) + || castlingRightsMask[castlingRookSquare[c | s]] != (c | s) + || (castlingRightsMask[square(c)] & (c | s)) != (c | s)) + assert(0 && "pos_is_ok: Castling"); + } + + return true; +} diff --git a/src/position.h b/src/position.h new file mode 100644 index 0000000..34e2f7e --- /dev/null +++ b/src/position.h @@ -0,0 +1,427 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef POSITION_H_INCLUDED +#define POSITION_H_INCLUDED + +#include +#include +#include // For std::unique_ptr +#include + +#include "bitboard.h" +#include "types.h" + + +/// StateInfo struct stores information needed to restore a Position object to +/// its previous state when we retract a move. Whenever a move is made on the +/// board (by calling Position::do_move), a StateInfo object must be passed. + +struct StateInfo { + + // Copied when making a move + Key pawnKey; + Key materialKey; + Value nonPawnMaterial[COLOR_NB]; + int castlingRights; + int rule50; + int pliesFromNull; + Score psq; + Square epSquare; + + // Not copied when making a move (will be recomputed anyhow) + Key key; + Bitboard checkersBB; + Piece capturedPiece; + StateInfo* previous; + Bitboard blockersForKing[COLOR_NB]; + Bitboard pinnersForKing[COLOR_NB]; + Bitboard checkSquares[PIECE_TYPE_NB]; +}; + +/// A list to keep track of the position states along the setup moves (from the +/// start position to the position just before the search starts). Needed by +/// 'draw by repetition' detection. Use a std::deque because pointers to +/// elements are not invalidated upon list resizing. +typedef std::unique_ptr> StateListPtr; + + +/// Position class stores information regarding the board representation as +/// pieces, side to move, hash keys, castling info, etc. Important methods are +/// do_move() and undo_move(), used by the search to update node info when +/// traversing the search tree. +class Thread; + +class Position { +public: + static void init(); + + Position() = default; + Position(const Position&) = delete; + Position& operator=(const Position&) = delete; + + // FEN string input/output + Position& set(const std::string& fenStr, bool isChess960, StateInfo* si, Thread* th); + Position& set(const std::string& code, Color c, StateInfo* si); + const std::string fen() const; + + // Position representation + Bitboard pieces() const; + Bitboard pieces(PieceType pt) const; + Bitboard pieces(PieceType pt1, PieceType pt2) const; + Bitboard pieces(Color c) const; + Bitboard pieces(Color c, PieceType pt) const; + Bitboard pieces(Color c, PieceType pt1, PieceType pt2) const; + Piece piece_on(Square s) const; + Square ep_square() const; + bool empty(Square s) const; + template int count(Color c) const; + template int count() const; + template const Square* squares(Color c) const; + template Square square(Color c) const; + + // Castling + int can_castle(Color c) const; + int can_castle(CastlingRight cr) const; + bool castling_impeded(CastlingRight cr) const; + Square castling_rook_square(CastlingRight cr) const; + + // Checking + Bitboard checkers() const; + Bitboard discovered_check_candidates() const; + Bitboard pinned_pieces(Color c) const; + Bitboard check_squares(PieceType pt) const; + + // Attacks to/from a given square + Bitboard attackers_to(Square s) const; + Bitboard attackers_to(Square s, Bitboard occupied) const; + Bitboard attacks_from(PieceType pt, Square s) const; + template Bitboard attacks_from(Square s) const; + template Bitboard attacks_from(Square s, Color c) const; + Bitboard slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const; + + // Properties of moves + bool legal(Move m) const; + bool pseudo_legal(const Move m) const; + bool capture(Move m) const; + bool capture_or_promotion(Move m) const; + bool gives_check(Move m) const; + bool advanced_pawn_push(Move m) const; + Piece moved_piece(Move m) const; + Piece captured_piece() const; + + // Piece specific + bool pawn_passed(Color c, Square s) const; + bool opposite_bishops() const; + + // Doing and undoing moves + void do_move(Move m, StateInfo& newSt); + void do_move(Move m, StateInfo& newSt, bool givesCheck); + void undo_move(Move m); + void do_null_move(StateInfo& newSt); + void undo_null_move(); + + // Static Exchange Evaluation + bool see_ge(Move m, Value threshold = VALUE_ZERO) const; + + // Accessing hash keys + Key key() const; + Key key_after(Move m) const; + Key material_key() const; + Key pawn_key() const; + + // Other properties of the position + Color side_to_move() const; + int game_ply() const; + bool is_chess960() const; + Thread* this_thread() const; + bool is_draw(int ply) const; + int rule50_count() const; + Score psq_score() const; + Value non_pawn_material(Color c) const; + Value non_pawn_material() const; + + // Position consistency check, for debugging + bool pos_is_ok() const; + void flip(); + +private: + // Initialization helpers (used while setting up a position) + void set_castling_right(Color c, Square rfrom); + void set_state(StateInfo* si) const; + void set_check_info(StateInfo* si) const; + + // Other helpers + void put_piece(Piece pc, Square s); + void remove_piece(Piece pc, Square s); + void move_piece(Piece pc, Square from, Square to); + template + void do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto); + + // Data members + Piece board[SQUARE_NB]; + Bitboard byTypeBB[PIECE_TYPE_NB]; + Bitboard byColorBB[COLOR_NB]; + int pieceCount[PIECE_NB]; + Square pieceList[PIECE_NB][16]; + int index[SQUARE_NB]; + int castlingRightsMask[SQUARE_NB]; + Square castlingRookSquare[CASTLING_RIGHT_NB]; + Bitboard castlingPath[CASTLING_RIGHT_NB]; + int gamePly; + Color sideToMove; + Thread* thisThread; + StateInfo* st; + bool chess960; +}; + +extern std::ostream& operator<<(std::ostream& os, const Position& pos); + +inline Color Position::side_to_move() const { + return sideToMove; +} + +inline bool Position::empty(Square s) const { + return board[s] == NO_PIECE; +} + +inline Piece Position::piece_on(Square s) const { + return board[s]; +} + +inline Piece Position::moved_piece(Move m) const { + return board[from_sq(m)]; +} + +inline Bitboard Position::pieces() const { + return byTypeBB[ALL_PIECES]; +} + +inline Bitboard Position::pieces(PieceType pt) const { + return byTypeBB[pt]; +} + +inline Bitboard Position::pieces(PieceType pt1, PieceType pt2) const { + return byTypeBB[pt1] | byTypeBB[pt2]; +} + +inline Bitboard Position::pieces(Color c) const { + return byColorBB[c]; +} + +inline Bitboard Position::pieces(Color c, PieceType pt) const { + return byColorBB[c] & byTypeBB[pt]; +} + +inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const { + return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]); +} + +template inline int Position::count(Color c) const { + return pieceCount[make_piece(c, Pt)]; +} + +template inline int Position::count() const { + return pieceCount[make_piece(WHITE, Pt)] + pieceCount[make_piece(BLACK, Pt)]; +} + +template inline const Square* Position::squares(Color c) const { + return pieceList[make_piece(c, Pt)]; +} + +template inline Square Position::square(Color c) const { + assert(pieceCount[make_piece(c, Pt)] == 1); + return pieceList[make_piece(c, Pt)][0]; +} + +inline Square Position::ep_square() const { + return st->epSquare; +} + +inline int Position::can_castle(CastlingRight cr) const { + return st->castlingRights & cr; +} + +inline int Position::can_castle(Color c) const { + return st->castlingRights & ((WHITE_OO | WHITE_OOO) << (2 * c)); +} + +inline bool Position::castling_impeded(CastlingRight cr) const { + return byTypeBB[ALL_PIECES] & castlingPath[cr]; +} + +inline Square Position::castling_rook_square(CastlingRight cr) const { + return castlingRookSquare[cr]; +} + +template +inline Bitboard Position::attacks_from(Square s) const { + assert(Pt != PAWN); + return Pt == BISHOP || Pt == ROOK ? attacks_bb(s, byTypeBB[ALL_PIECES]) + : Pt == QUEEN ? attacks_from(s) | attacks_from(s) + : PseudoAttacks[Pt][s]; +} + +template<> +inline Bitboard Position::attacks_from(Square s, Color c) const { + return PawnAttacks[c][s]; +} + +inline Bitboard Position::attacks_from(PieceType pt, Square s) const { + return attacks_bb(pt, s, byTypeBB[ALL_PIECES]); +} + +inline Bitboard Position::attackers_to(Square s) const { + return attackers_to(s, byTypeBB[ALL_PIECES]); +} + +inline Bitboard Position::checkers() const { + return st->checkersBB; +} + +inline Bitboard Position::discovered_check_candidates() const { + return st->blockersForKing[~sideToMove] & pieces(sideToMove); +} + +inline Bitboard Position::pinned_pieces(Color c) const { + return st->blockersForKing[c] & pieces(c); +} + +inline Bitboard Position::check_squares(PieceType pt) const { + return st->checkSquares[pt]; +} + +inline bool Position::pawn_passed(Color c, Square s) const { + return !(pieces(~c, PAWN) & passed_pawn_mask(c, s)); +} + +inline bool Position::advanced_pawn_push(Move m) const { + return type_of(moved_piece(m)) == PAWN + && relative_rank(sideToMove, from_sq(m)) > RANK_4; +} + +inline Key Position::key() const { + return st->key; +} + +inline Key Position::pawn_key() const { + return st->pawnKey; +} + +inline Key Position::material_key() const { + return st->materialKey; +} + +inline Score Position::psq_score() const { + return st->psq; +} + +inline Value Position::non_pawn_material(Color c) const { + return st->nonPawnMaterial[c]; +} + +inline Value Position::non_pawn_material() const { + return st->nonPawnMaterial[WHITE] + st->nonPawnMaterial[BLACK]; +} + +inline int Position::game_ply() const { + return gamePly; +} + +inline int Position::rule50_count() const { + return st->rule50; +} + +inline bool Position::opposite_bishops() const { + return pieceCount[W_BISHOP] == 1 + && pieceCount[B_BISHOP] == 1 + && opposite_colors(square(WHITE), square(BLACK)); +} + +inline bool Position::is_chess960() const { + return chess960; +} + +inline bool Position::capture_or_promotion(Move m) const { + assert(is_ok(m)); + return type_of(m) != NORMAL ? type_of(m) != CASTLING : !empty(to_sq(m)); +} + +inline bool Position::capture(Move m) const { + assert(is_ok(m)); + // Castling is encoded as "king captures rook" + return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == ENPASSANT; +} + +inline Piece Position::captured_piece() const { + return st->capturedPiece; +} + +inline Thread* Position::this_thread() const { + return thisThread; +} + +inline void Position::put_piece(Piece pc, Square s) { + + board[s] = pc; + byTypeBB[ALL_PIECES] |= s; + byTypeBB[type_of(pc)] |= s; + byColorBB[color_of(pc)] |= s; + index[s] = pieceCount[pc]++; + pieceList[pc][index[s]] = s; + pieceCount[make_piece(color_of(pc), ALL_PIECES)]++; +} + +inline void Position::remove_piece(Piece pc, Square s) { + + // WARNING: This is not a reversible operation. If we remove a piece in + // do_move() and then replace it in undo_move() we will put it at the end of + // the list and not in its original place, it means index[] and pieceList[] + // are not invariant to a do_move() + undo_move() sequence. + byTypeBB[ALL_PIECES] ^= s; + byTypeBB[type_of(pc)] ^= s; + byColorBB[color_of(pc)] ^= s; + /* board[s] = NO_PIECE; Not needed, overwritten by the capturing one */ + Square lastSquare = pieceList[pc][--pieceCount[pc]]; + index[lastSquare] = index[s]; + pieceList[pc][index[lastSquare]] = lastSquare; + pieceList[pc][pieceCount[pc]] = SQ_NONE; + pieceCount[make_piece(color_of(pc), ALL_PIECES)]--; +} + +inline void Position::move_piece(Piece pc, Square from, Square to) { + + // index[from] is not updated and becomes stale. This works as long as index[] + // is accessed just by known occupied squares. + Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to]; + byTypeBB[ALL_PIECES] ^= from_to_bb; + byTypeBB[type_of(pc)] ^= from_to_bb; + byColorBB[color_of(pc)] ^= from_to_bb; + board[from] = NO_PIECE; + board[to] = pc; + index[to] = index[from]; + pieceList[pc][index[to]] = to; +} + +inline void Position::do_move(Move m, StateInfo& newSt) { + do_move(m, newSt, gives_check(m)); +} + +#endif // #ifndef POSITION_H_INCLUDED diff --git a/src/psqt.cpp b/src/psqt.cpp new file mode 100644 index 0000000..3f447dc --- /dev/null +++ b/src/psqt.cpp @@ -0,0 +1,126 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include + +#include "types.h" + +Value PieceValue[PHASE_NB][PIECE_NB] = { + { VALUE_ZERO, PawnValueMg, KnightValueMg, BishopValueMg, RookValueMg, QueenValueMg }, + { VALUE_ZERO, PawnValueEg, KnightValueEg, BishopValueEg, RookValueEg, QueenValueEg } +}; + +namespace PSQT { + +#define S(mg, eg) make_score(mg, eg) + +// Bonus[PieceType][Square / 2] contains Piece-Square scores. For each piece +// type on a given square a (middlegame, endgame) score pair is assigned. Table +// is defined for files A..D and white side: it is symmetric for black side and +// second half of the files. +const Score Bonus[][RANK_NB][int(FILE_NB) / 2] = { + { }, + { // Pawn + { S( 0, 0), S( 0, 0), S( 0, 0), S( 0, 0) }, + { S(-11, 7), S( 6,-4), S( 7, 8), S( 3,-2) }, + { S(-18,-4), S( -2,-5), S( 19, 5), S(24, 4) }, + { S(-17, 3), S( -9, 3), S( 20,-8), S(35,-3) }, + { S( -6, 8), S( 5, 9), S( 3, 7), S(21,-6) }, + { S( -6, 8), S( -8,-5), S( -6, 2), S(-2, 4) }, + { S( -4, 3), S( 20,-9), S( -8, 1), S(-4,18) } + }, + { // Knight + { S(-161,-105), S(-96,-82), S(-80,-46), S(-73,-14) }, + { S( -83, -69), S(-43,-54), S(-21,-17), S(-10, 9) }, + { S( -71, -50), S(-22,-39), S( 0, -7), S( 9, 28) }, + { S( -25, -41), S( 18,-25), S( 43, 6), S( 47, 38) }, + { S( -26, -46), S( 16,-25), S( 38, 3), S( 50, 40) }, + { S( -11, -54), S( 37,-38), S( 56, -7), S( 65, 27) }, + { S( -63, -65), S(-19,-50), S( 5,-24), S( 14, 13) }, + { S(-195,-109), S(-67,-89), S(-42,-50), S(-29,-13) } + }, + { // Bishop + { S(-44,-58), S(-13,-31), S(-25,-37), S(-34,-19) }, + { S(-20,-34), S( 20, -9), S( 12,-14), S( 1, 4) }, + { S( -9,-23), S( 27, 0), S( 21, -3), S( 11, 16) }, + { S(-11,-26), S( 28, -3), S( 21, -5), S( 10, 16) }, + { S(-11,-26), S( 27, -4), S( 16, -7), S( 9, 14) }, + { S(-17,-24), S( 16, -2), S( 12, 0), S( 2, 13) }, + { S(-23,-34), S( 17,-10), S( 6,-12), S( -2, 6) }, + { S(-35,-55), S(-11,-32), S(-19,-36), S(-29,-17) } + }, + { // Rook + { S(-25, 0), S(-16, 0), S(-16, 0), S(-9, 0) }, + { S(-21, 0), S( -8, 0), S( -3, 0), S( 0, 0) }, + { S(-21, 0), S( -9, 0), S( -4, 0), S( 2, 0) }, + { S(-22, 0), S( -6, 0), S( -1, 0), S( 2, 0) }, + { S(-22, 0), S( -7, 0), S( 0, 0), S( 1, 0) }, + { S(-21, 0), S( -7, 0), S( 0, 0), S( 2, 0) }, + { S(-12, 0), S( 4, 0), S( 8, 0), S(12, 0) }, + { S(-23, 0), S(-15, 0), S(-11, 0), S(-5, 0) } + }, + { // Queen + { S( 0,-71), S(-4,-56), S(-3,-42), S(-1,-29) }, + { S(-4,-56), S( 6,-30), S( 9,-21), S( 8, -5) }, + { S(-2,-39), S( 6,-17), S( 9, -8), S( 9, 5) }, + { S(-1,-29), S( 8, -5), S(10, 9), S( 7, 19) }, + { S(-3,-27), S( 9, -5), S( 8, 10), S( 7, 21) }, + { S(-2,-40), S( 6,-16), S( 8,-10), S(10, 3) }, + { S(-2,-55), S( 7,-30), S( 7,-21), S( 6, -6) }, + { S(-1,-74), S(-4,-55), S(-1,-43), S( 0,-30) } + }, + { // King + { S(267, 0), S(320, 48), S(270, 75), S(195, 84) }, + { S(264, 43), S(304, 92), S(238,143), S(180,132) }, + { S(200, 83), S(245,138), S(176,167), S(110,165) }, + { S(177,106), S(185,169), S(148,169), S(110,179) }, + { S(149,108), S(177,163), S(115,200), S( 66,203) }, + { S(118, 95), S(159,155), S( 84,176), S( 41,174) }, + { S( 87, 50), S(128, 99), S( 63,122), S( 20,139) }, + { S( 63, 9), S( 88, 55), S( 47, 80), S( 0, 90) } + } +}; + +#undef S + +Score psq[PIECE_NB][SQUARE_NB]; + +// init() initializes piece-square tables: the white halves of the tables are +// copied from Bonus[] adding the piece value, then the black halves of the +// tables are initialized by flipping and changing the sign of the white scores. +void init() { + + for (Piece pc = W_PAWN; pc <= W_KING; ++pc) + { + PieceValue[MG][~pc] = PieceValue[MG][pc]; + PieceValue[EG][~pc] = PieceValue[EG][pc]; + + Score v = make_score(PieceValue[MG][pc], PieceValue[EG][pc]); + + for (Square s = SQ_A1; s <= SQ_H8; ++s) + { + File f = std::min(file_of(s), ~file_of(s)); + psq[ pc][ s] = v + Bonus[pc][rank_of(s)][f]; + psq[~pc][~s] = -psq[pc][s]; + } + } +} + +} // namespace PSQT diff --git a/src/search.cpp b/src/search.cpp new file mode 100644 index 0000000..b9ce9a6 --- /dev/null +++ b/src/search.cpp @@ -0,0 +1,1653 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include +#include // For std::memset +#include +#include + +#include "evaluate.h" +#include "misc.h" +#include "movegen.h" +#include "movepick.h" +#include "position.h" +#include "search.h" +#include "timeman.h" +#include "thread.h" +#include "tt.h" +#include "uci.h" +#include "syzygy/tbprobe.h" + +namespace Search { + + LimitsType Limits; +} + +namespace Tablebases { + + int Cardinality; + bool RootInTB; + bool UseRule50; + Depth ProbeDepth; + Value Score; +} + +namespace TB = Tablebases; + +using std::string; +using Eval::evaluate; +using namespace Search; + +namespace { + + // Different node types, used as a template parameter + enum NodeType { NonPV, PV }; + + // Sizes and phases of the skip-blocks, used for distributing search depths across the threads + const int skipSize[] = { 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4 }; + const int skipPhase[] = { 0, 1, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 7 }; + + // Razoring and futility margin based on depth + const int razor_margin = 600; + Value futility_margin(Depth d) { return Value(150 * d / ONE_PLY); } + + // Futility and reductions lookup tables, initialized at startup + int FutilityMoveCounts[2][16]; // [improving][depth] + int Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber] + + template Depth reduction(bool i, Depth d, int mn) { + return Reductions[PvNode][i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] * ONE_PLY; + } + + // History and stats update bonus, based on depth + int stat_bonus(Depth depth) { + int d = depth / ONE_PLY; + return d > 17 ? 0 : d * d + 2 * d - 2; + } + + // Skill structure is used to implement strength limit + struct Skill { + explicit Skill(int l) : level(l) {} + bool enabled() const { return level < 20; } + bool time_to_pick(Depth depth) const { return depth / ONE_PLY == 1 + level; } + Move pick_best(size_t multiPV); + + int level; + Move best = MOVE_NONE; + }; + + template + Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning); + + template + Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth = DEPTH_ZERO); + + Value value_to_tt(Value v, int ply); + Value value_from_tt(Value v, int ply); + void update_pv(Move* pv, Move move, Move* childPv); + void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus); + void update_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, int bonus); + void update_capture_stats(const Position& pos, Move move, Move* captures, int captureCnt, int bonus); + bool pv_is_draw(Position& pos); + + // perft() is our utility to verify move generation. All the leaf nodes up + // to the given depth are generated and counted, and the sum is returned. + template + uint64_t perft(Position& pos, Depth depth) { + + StateInfo st; + uint64_t cnt, nodes = 0; + const bool leaf = (depth == 2 * ONE_PLY); + + for (const auto& m : MoveList(pos)) + { + if (Root && depth <= ONE_PLY) + cnt = 1, nodes++; + else + { + pos.do_move(m, st); + cnt = leaf ? MoveList(pos).size() : perft(pos, depth - ONE_PLY); + nodes += cnt; + pos.undo_move(m); + } + if (Root) + sync_cout << UCI::move(m, pos.is_chess960()) << ": " << cnt << sync_endl; + } + return nodes; + } + +} // namespace + + +/// Search::init() is called during startup to initialize various lookup tables + +void Search::init() { + + for (int imp = 0; imp <= 1; ++imp) + for (int d = 1; d < 64; ++d) + for (int mc = 1; mc < 64; ++mc) + { + double r = log(d) * log(mc) / 1.95; + + Reductions[NonPV][imp][d][mc] = int(std::round(r)); + Reductions[PV][imp][d][mc] = std::max(Reductions[NonPV][imp][d][mc] - 1, 0); + + // Increase reduction for non-PV nodes when eval is not improving + if (!imp && Reductions[NonPV][imp][d][mc] >= 2) + Reductions[NonPV][imp][d][mc]++; + } + + for (int d = 0; d < 16; ++d) + { + FutilityMoveCounts[0][d] = int(2.4 + 0.74 * pow(d, 1.78)); + FutilityMoveCounts[1][d] = int(5.0 + 1.00 * pow(d, 2.00)); + } +} + + +/// Search::clear() resets search state to its initial value + +void Search::clear() { + + Threads.main()->wait_for_search_finished(); + + Time.availableNodes = 0; + TT.clear(); + Threads.clear(); +} + + +/// MainThread::search() is called by the main thread when the program receives +/// the UCI 'go' command. It searches from the root position and outputs the "bestmove". + +void MainThread::search() { + + if (Limits.perft) + { + nodes = perft(rootPos, Limits.perft * ONE_PLY); + sync_cout << "\nNodes searched: " << nodes << "\n" << sync_endl; + return; + } + + Color us = rootPos.side_to_move(); + Time.init(Limits, us, rootPos.game_ply()); + TT.new_search(); + + int contempt = Options["Contempt"] * PawnValueEg / 100; // From centipawns + + Eval::Contempt = (us == WHITE ? make_score(contempt, contempt / 2) + : -make_score(contempt, contempt / 2)); + + if (rootMoves.empty()) + { + rootMoves.emplace_back(MOVE_NONE); + sync_cout << "info depth 0 score " + << UCI::value(rootPos.checkers() ? -VALUE_MATE : VALUE_DRAW) + << sync_endl; + } + else + { + for (Thread* th : Threads) + if (th != this) + th->start_searching(); + + Thread::search(); // Let's start searching! + } + + // When we reach the maximum depth, we can arrive here without a raise of + // Threads.stop. However, if we are pondering or in an infinite search, + // the UCI protocol states that we shouldn't print the best move before the + // GUI sends a "stop" or "ponderhit" command. We therefore simply wait here + // until the GUI sends one of those commands (which also raises Threads.stop). + Threads.stopOnPonderhit = true; + + while (!Threads.stop && (Threads.ponder || Limits.infinite)) + {} // Busy wait for a stop or a ponder reset + + // Stop the threads if not already stopped (also raise the stop if + // "ponderhit" just reset Threads.ponder). + Threads.stop = true; + + // Wait until all threads have finished + for (Thread* th : Threads) + if (th != this) + th->wait_for_search_finished(); + + // When playing in 'nodes as time' mode, subtract the searched nodes from + // the available ones before exiting. + if (Limits.npmsec) + Time.availableNodes += Limits.inc[us] - Threads.nodes_searched(); + + // Check if there are threads with a better score than main thread + Thread* bestThread = this; + if ( Options["MultiPV"] == 1 + && !Limits.depth + && !Skill(Options["Skill Level"]).enabled() + && rootMoves[0].pv[0] != MOVE_NONE) + { + for (Thread* th : Threads) + { + Depth depthDiff = th->completedDepth - bestThread->completedDepth; + Value scoreDiff = th->rootMoves[0].score - bestThread->rootMoves[0].score; + + // Select the thread with the best score, always if it is a mate + if ( scoreDiff > 0 + && (depthDiff >= 0 || th->rootMoves[0].score >= VALUE_MATE_IN_MAX_PLY)) + bestThread = th; + } + } + + previousScore = bestThread->rootMoves[0].score; + + // Send new PV when needed + if (bestThread != this) + sync_cout << UCI::pv(bestThread->rootPos, bestThread->completedDepth, -VALUE_INFINITE, VALUE_INFINITE) << sync_endl; + + sync_cout << "bestmove " << UCI::move(bestThread->rootMoves[0].pv[0], rootPos.is_chess960()); + + if (bestThread->rootMoves[0].pv.size() > 1 || bestThread->rootMoves[0].extract_ponder_from_tt(rootPos)) + std::cout << " ponder " << UCI::move(bestThread->rootMoves[0].pv[1], rootPos.is_chess960()); + + std::cout << sync_endl; +} + + +/// Thread::search() is the main iterative deepening loop. It calls search() +/// repeatedly with increasing depth until the allocated thinking time has been +/// consumed, the user stops the search, or the maximum search depth is reached. + +void Thread::search() { + + Stack stack[MAX_PLY+7], *ss = stack+4; // To reference from (ss-4) to (ss+2) + Value bestValue, alpha, beta, delta; + Move lastBestMove = MOVE_NONE; + Depth lastBestMoveDepth = DEPTH_ZERO; + MainThread* mainThread = (this == Threads.main() ? Threads.main() : nullptr); + double timeReduction = 1.0; + + std::memset(ss-4, 0, 7 * sizeof(Stack)); + for (int i = 4; i > 0; i--) + (ss-i)->contHistory = &this->contHistory[NO_PIECE][0]; // Use as sentinel + + bestValue = delta = alpha = -VALUE_INFINITE; + beta = VALUE_INFINITE; + + if (mainThread) + { + mainThread->failedLow = false; + mainThread->bestMoveChanges = 0; + } + + size_t multiPV = Options["MultiPV"]; + Skill skill(Options["Skill Level"]); + + // When playing with strength handicap enable MultiPV search that we will + // use behind the scenes to retrieve a set of possible moves. + if (skill.enabled()) + multiPV = std::max(multiPV, (size_t)4); + + multiPV = std::min(multiPV, rootMoves.size()); + + // Iterative deepening loop until requested to stop or the target depth is reached + while ( (rootDepth += ONE_PLY) < DEPTH_MAX + && !Threads.stop + && !(Limits.depth && mainThread && rootDepth / ONE_PLY > Limits.depth)) + { + // Distribute search depths across the threads + if (idx) + { + int i = (idx - 1) % 20; + if (((rootDepth / ONE_PLY + rootPos.game_ply() + skipPhase[i]) / skipSize[i]) % 2) + continue; + } + + // Age out PV variability metric + if (mainThread) + mainThread->bestMoveChanges *= 0.505, mainThread->failedLow = false; + + // Save the last iteration's scores before first PV line is searched and + // all the move scores except the (new) PV are set to -VALUE_INFINITE. + for (RootMove& rm : rootMoves) + rm.previousScore = rm.score; + + // MultiPV loop. We perform a full root search for each PV line + for (PVIdx = 0; PVIdx < multiPV && !Threads.stop; ++PVIdx) + { + // Reset UCI info selDepth for each depth and each PV line + selDepth = 0; + + // Reset aspiration window starting size + if (rootDepth >= 5 * ONE_PLY) + { + delta = Value(18); + alpha = std::max(rootMoves[PVIdx].previousScore - delta,-VALUE_INFINITE); + beta = std::min(rootMoves[PVIdx].previousScore + delta, VALUE_INFINITE); + } + + // Start with a small aspiration window and, in the case of a fail + // high/low, re-search with a bigger window until we're not failing + // high/low anymore. + while (true) + { + bestValue = ::search(rootPos, ss, alpha, beta, rootDepth, false, false); + + // Bring the best move to the front. It is critical that sorting + // is done with a stable algorithm because all the values but the + // first and eventually the new best one are set to -VALUE_INFINITE + // and we want to keep the same order for all the moves except the + // new PV that goes to the front. Note that in case of MultiPV + // search the already searched PV lines are preserved. + std::stable_sort(rootMoves.begin() + PVIdx, rootMoves.end()); + + // If search has been stopped, we break immediately. Sorting and + // writing PV back to TT is safe because RootMoves is still + // valid, although it refers to the previous iteration. + if (Threads.stop) + break; + + // When failing high/low give some update (without cluttering + // the UI) before a re-search. + if ( mainThread + && multiPV == 1 + && (bestValue <= alpha || bestValue >= beta) + && Time.elapsed() > 3000) + sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl; + + // In case of failing low/high increase aspiration window and + // re-search, otherwise exit the loop. + if (bestValue <= alpha) + { + beta = (alpha + beta) / 2; + alpha = std::max(bestValue - delta, -VALUE_INFINITE); + + if (mainThread) + { + mainThread->failedLow = true; + Threads.stopOnPonderhit = false; + } + } + else if (bestValue >= beta) + beta = std::min(bestValue + delta, VALUE_INFINITE); + else + break; + + delta += delta / 4 + 5; + + assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE); + } + + // Sort the PV lines searched so far and update the GUI + std::stable_sort(rootMoves.begin(), rootMoves.begin() + PVIdx + 1); + + if ( mainThread + && (Threads.stop || PVIdx + 1 == multiPV || Time.elapsed() > 3000)) + sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl; + } + + if (!Threads.stop) + completedDepth = rootDepth; + + if (rootMoves[0].pv[0] != lastBestMove) { + lastBestMove = rootMoves[0].pv[0]; + lastBestMoveDepth = rootDepth; + } + + // Have we found a "mate in x"? + if ( Limits.mate + && bestValue >= VALUE_MATE_IN_MAX_PLY + && VALUE_MATE - bestValue <= 2 * Limits.mate) + Threads.stop = true; + + if (!mainThread) + continue; + + // If skill level is enabled and time is up, pick a sub-optimal best move + if (skill.enabled() && skill.time_to_pick(rootDepth)) + skill.pick_best(multiPV); + + // Do we have time for the next iteration? Can we stop searching now? + if (Limits.use_time_management()) + { + if (!Threads.stop && !Threads.stopOnPonderhit) + { + // Stop the search if only one legal move is available, or if all + // of the available time has been used + const int F[] = { mainThread->failedLow, + bestValue - mainThread->previousScore }; + int improvingFactor = std::max(229, std::min(715, 357 + 119 * F[0] - 6 * F[1])); + + Color us = rootPos.side_to_move(); + bool thinkHard = bestValue == VALUE_DRAW + && Limits.time[us] - Time.elapsed() > Limits.time[~us] + && ::pv_is_draw(rootPos); + + double unstablePvFactor = 1 + mainThread->bestMoveChanges + thinkHard; + + // if the bestMove is stable over several iterations, reduce time for this move, + // the longer the move has been stable, the more. + // Use part of the gained time from a previous stable move for the current move. + timeReduction = 1; + for (int i : {3, 4, 5}) + if (lastBestMoveDepth * i < completedDepth && !thinkHard) + timeReduction *= 1.3; + unstablePvFactor *= std::pow(mainThread->previousTimeReduction, 0.51) / timeReduction; + + if ( rootMoves.size() == 1 + || Time.elapsed() > Time.optimum() * unstablePvFactor * improvingFactor / 628) + { + // If we are allowed to ponder do not stop the search now but + // keep pondering until the GUI sends "ponderhit" or "stop". + if (Threads.ponder) + Threads.stopOnPonderhit = true; + else + Threads.stop = true; + } + } + } + } + + if (!mainThread) + return; + + mainThread->previousTimeReduction = timeReduction; + + // If skill level is enabled, swap best PV line with the sub-optimal one + if (skill.enabled()) + std::swap(rootMoves[0], *std::find(rootMoves.begin(), rootMoves.end(), + skill.best ? skill.best : skill.pick_best(multiPV))); +} + + +namespace { + + // search<>() is the main search function for both PV and non-PV nodes + + template + Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning) { + + const bool PvNode = NT == PV; + const bool rootNode = PvNode && ss->ply == 0; + + assert(-VALUE_INFINITE <= alpha && alpha < beta && beta <= VALUE_INFINITE); + assert(PvNode || (alpha == beta - 1)); + assert(DEPTH_ZERO < depth && depth < DEPTH_MAX); + assert(!(PvNode && cutNode)); + assert(depth / ONE_PLY * ONE_PLY == depth); + + Move pv[MAX_PLY+1], capturesSearched[32], quietsSearched[64]; + StateInfo st; + TTEntry* tte; + Key posKey; + Move ttMove, move, excludedMove, bestMove; + Depth extension, newDepth; + Value bestValue, value, ttValue, eval, maxValue; + bool ttHit, inCheck, givesCheck, singularExtensionNode, improving; + bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture, pvExact; + Piece movedPiece; + int moveCount, captureCount, quietCount; + + // Step 1. Initialize node + Thread* thisThread = pos.this_thread(); + inCheck = pos.checkers(); + moveCount = captureCount = quietCount = ss->moveCount = 0; + ss->statScore = 0; + bestValue = -VALUE_INFINITE; + maxValue = VALUE_INFINITE; + + // Check for the available remaining time + if (thisThread == Threads.main()) + static_cast(thisThread)->check_time(); + + // Used to send selDepth info to GUI (selDepth counts from 1, ply from 0) + if (PvNode && thisThread->selDepth < ss->ply + 1) + thisThread->selDepth = ss->ply + 1; + + if (!rootNode) + { + // Step 2. Check for aborted search and immediate draw + if (Threads.stop.load(std::memory_order_relaxed) || pos.is_draw(ss->ply) || ss->ply >= MAX_PLY) + return ss->ply >= MAX_PLY && !inCheck ? evaluate(pos) : VALUE_DRAW; + + // Step 3. Mate distance pruning. Even if we mate at the next move our score + // would be at best mate_in(ss->ply+1), but if alpha is already bigger because + // a shorter mate was found upward in the tree then there is no need to search + // because we will never beat the current alpha. Same logic but with reversed + // signs applies also in the opposite condition of being mated instead of giving + // mate. In this case return a fail-high score. + alpha = std::max(mated_in(ss->ply), alpha); + beta = std::min(mate_in(ss->ply+1), beta); + if (alpha >= beta) + return alpha; + } + + assert(0 <= ss->ply && ss->ply < MAX_PLY); + + (ss+1)->ply = ss->ply + 1; + ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE; + ss->contHistory = &thisThread->contHistory[NO_PIECE][0]; + (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; + Square prevSq = to_sq((ss-1)->currentMove); + + // Step 4. Transposition table lookup. We don't want the score of a partial + // search to overwrite a previous full search TT value, so we use a different + // position key in case of an excluded move. + excludedMove = ss->excludedMove; + posKey = pos.key() ^ Key(excludedMove << 16); // isn't a very good hash + tte = TT.probe(posKey, ttHit); + ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE; + ttMove = rootNode ? thisThread->rootMoves[thisThread->PVIdx].pv[0] + : ttHit ? tte->move() : MOVE_NONE; + + // At non-PV nodes we check for an early TT cutoff + if ( !PvNode + && ttHit + && tte->depth() >= depth + && ttValue != VALUE_NONE // Possible in case of TT access race + && (ttValue >= beta ? (tte->bound() & BOUND_LOWER) + : (tte->bound() & BOUND_UPPER))) + { + // If ttMove is quiet, update move sorting heuristics on TT hit + if (ttMove) + { + if (ttValue >= beta) + { + if (!pos.capture_or_promotion(ttMove)) + update_stats(pos, ss, ttMove, nullptr, 0, stat_bonus(depth)); + + // Extra penalty for a quiet TT move in previous ply when it gets refuted + if ((ss-1)->moveCount == 1 && !pos.captured_piece()) + update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY)); + } + // Penalty for a quiet ttMove that fails low + else if (!pos.capture_or_promotion(ttMove)) + { + int penalty = -stat_bonus(depth); + thisThread->mainHistory.update(pos.side_to_move(), ttMove, penalty); + update_continuation_histories(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty); + } + } + return ttValue; + } + + // Step 4a. Tablebase probe + if (!rootNode && TB::Cardinality) + { + int piecesCount = pos.count(); + + if ( piecesCount <= TB::Cardinality + && (piecesCount < TB::Cardinality || depth >= TB::ProbeDepth) + && pos.rule50_count() == 0 + && !pos.can_castle(ANY_CASTLING)) + { + TB::ProbeState err; + TB::WDLScore wdl = Tablebases::probe_wdl(pos, &err); + + if (err != TB::ProbeState::FAIL) + { + thisThread->tbHits.fetch_add(1, std::memory_order_relaxed); + + int drawScore = TB::UseRule50 ? 1 : 0; + + value = wdl < -drawScore ? -VALUE_MATE + MAX_PLY + ss->ply + 1 + : wdl > drawScore ? VALUE_MATE - MAX_PLY - ss->ply - 1 + : VALUE_DRAW + 2 * wdl * drawScore; + + Bound b = wdl < -drawScore ? BOUND_UPPER + : wdl > drawScore ? BOUND_LOWER : BOUND_EXACT; + + if ( b == BOUND_EXACT + || (b == BOUND_LOWER ? value >= beta : value <= alpha)) + { + tte->save(posKey, value_to_tt(value, ss->ply), b, + std::min(DEPTH_MAX - ONE_PLY, depth + 6 * ONE_PLY), + MOVE_NONE, VALUE_NONE, TT.generation()); + + return value; + } + + if (PvNode) + { + if (b == BOUND_LOWER) + bestValue = value, alpha = std::max(alpha, bestValue); + else + maxValue = value; + } + } + } + } + + // Step 5. Evaluate the position statically + if (inCheck) + { + ss->staticEval = eval = VALUE_NONE; + goto moves_loop; + } + + else if (ttHit) + { + // Never assume anything on values stored in TT + if ((ss->staticEval = eval = tte->eval()) == VALUE_NONE) + eval = ss->staticEval = evaluate(pos); + + // Can ttValue be used as a better position evaluation? + if ( ttValue != VALUE_NONE + && (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER))) + eval = ttValue; + } + else + { + eval = ss->staticEval = + (ss-1)->currentMove != MOVE_NULL ? evaluate(pos) + : -(ss-1)->staticEval + 2 * Eval::Tempo; + + tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, + ss->staticEval, TT.generation()); + } + + if (skipEarlyPruning || !pos.non_pawn_material(pos.side_to_move())) + goto moves_loop; + + // Step 6. Razoring (skipped when in check) + if ( !PvNode + && depth < 4 * ONE_PLY + && eval + razor_margin <= alpha) + { + if (depth <= ONE_PLY) + return qsearch(pos, ss, alpha, alpha+1); + + Value ralpha = alpha - razor_margin; + Value v = qsearch(pos, ss, ralpha, ralpha+1); + if (v <= ralpha) + return v; + } + + // Step 7. Futility pruning: child node (skipped when in check) + if ( !rootNode + && depth < 7 * ONE_PLY + && eval - futility_margin(depth) >= beta + && eval < VALUE_KNOWN_WIN) // Do not return unproven wins + return eval; + + // Step 8. Null move search with verification search (is omitted in PV nodes) + if ( !PvNode + && eval >= beta + && ss->staticEval >= beta - 36 * depth / ONE_PLY + 225 + && (ss->ply >= thisThread->nmp_ply || ss->ply % 2 != thisThread->nmp_odd)) + { + + assert(eval - beta >= 0); + + // Null move dynamic reduction based on depth and value + Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY; + + ss->currentMove = MOVE_NULL; + ss->contHistory = &thisThread->contHistory[NO_PIECE][0]; + + pos.do_null_move(st); + Value nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1) + : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode, true); + pos.undo_null_move(); + + if (nullValue >= beta) + { + // Do not return unproven mate scores + if (nullValue >= VALUE_MATE_IN_MAX_PLY) + nullValue = beta; + + if (abs(beta) < VALUE_KNOWN_WIN && (depth < 12 * ONE_PLY || thisThread->nmp_ply)) + return nullValue; + + // Do verification search at high depths + // disable null move pruning for side to move for the first part of the remaining search tree + thisThread->nmp_ply = ss->ply + 3 * (depth-R) / 4; + thisThread->nmp_odd = ss->ply % 2; + + Value v = depth-R < ONE_PLY ? qsearch(pos, ss, beta-1, beta) + : search(pos, ss, beta-1, beta, depth-R, false, true); + + thisThread->nmp_odd = thisThread->nmp_ply = 0; + + if (v >= beta) + return nullValue; + } + } + + // Step 9. ProbCut (skipped when in check) + // If we have a good enough capture and a reduced search returns a value + // much above beta, we can (almost) safely prune the previous move. + if ( !PvNode + && depth >= 5 * ONE_PLY + && abs(beta) < VALUE_MATE_IN_MAX_PLY) + { + Value rbeta = std::min(beta + 200, VALUE_INFINITE); + + assert(is_ok((ss-1)->currentMove)); + + MovePicker mp(pos, ttMove, rbeta - ss->staticEval, &thisThread->captureHistory); + + while ((move = mp.next_move()) != MOVE_NONE) + if (pos.legal(move)) + { + ss->currentMove = move; + ss->contHistory = &thisThread->contHistory[pos.moved_piece(move)][to_sq(move)]; + + assert(depth >= 5 * ONE_PLY); + pos.do_move(move, st); + value = -search(pos, ss+1, -rbeta, -rbeta+1, depth - 4 * ONE_PLY, !cutNode, false); + pos.undo_move(move); + if (value >= rbeta) + return value; + } + } + + // Step 10. Internal iterative deepening (skipped when in check) + if ( depth >= 6 * ONE_PLY + && !ttMove + && (PvNode || ss->staticEval + 256 >= beta)) + { + Depth d = (3 * depth / (4 * ONE_PLY) - 2) * ONE_PLY; + search(pos, ss, alpha, beta, d, cutNode, true); + + tte = TT.probe(posKey, ttHit); + ttMove = ttHit ? tte->move() : MOVE_NONE; + } + +moves_loop: // When in check search starts from here + + const PieceToHistory* contHist[] = { (ss-1)->contHistory, (ss-2)->contHistory, nullptr, (ss-4)->contHistory }; + Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]; + + MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, &thisThread->captureHistory, contHist, countermove, ss->killers); + value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc + improving = ss->staticEval >= (ss-2)->staticEval + /* || ss->staticEval == VALUE_NONE Already implicit in the previous condition */ + ||(ss-2)->staticEval == VALUE_NONE; + + singularExtensionNode = !rootNode + && depth >= 8 * ONE_PLY + && ttMove != MOVE_NONE + && ttValue != VALUE_NONE + && !excludedMove // Recursive singular search is not allowed + && (tte->bound() & BOUND_LOWER) + && tte->depth() >= depth - 3 * ONE_PLY; + skipQuiets = false; + ttCapture = false; + pvExact = PvNode && ttHit && tte->bound() == BOUND_EXACT; + + // Step 11. Loop through moves + // Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs + while ((move = mp.next_move(skipQuiets)) != MOVE_NONE) + { + assert(is_ok(move)); + + if (move == excludedMove) + continue; + + // At root obey the "searchmoves" option and skip moves not listed in Root + // Move List. As a consequence any illegal move is also skipped. In MultiPV + // mode we also skip PV moves which have been already searched. + if (rootNode && !std::count(thisThread->rootMoves.begin() + thisThread->PVIdx, + thisThread->rootMoves.end(), move)) + continue; + + ss->moveCount = ++moveCount; + + if (rootNode && thisThread == Threads.main() && Time.elapsed() > 3000) + sync_cout << "info depth " << depth / ONE_PLY + << " currmove " << UCI::move(move, pos.is_chess960()) + << " currmovenumber " << moveCount + thisThread->PVIdx << sync_endl; + + if (PvNode) + (ss+1)->pv = nullptr; + + extension = DEPTH_ZERO; + captureOrPromotion = pos.capture_or_promotion(move); + movedPiece = pos.moved_piece(move); + + givesCheck = type_of(move) == NORMAL && !pos.discovered_check_candidates() + ? pos.check_squares(type_of(movedPiece)) & to_sq(move) + : pos.gives_check(move); + + moveCountPruning = depth < 16 * ONE_PLY + && moveCount >= FutilityMoveCounts[improving][depth / ONE_PLY]; + + // Step 12. Singular and Gives Check Extensions + + // Singular extension search. If all moves but one fail low on a search of + // (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move + // is singular and should be extended. To verify this we do a reduced search + // on all the other moves but the ttMove and if the result is lower than + // ttValue minus a margin then we will extend the ttMove. + if ( singularExtensionNode + && move == ttMove + && pos.legal(move)) + { + Value rBeta = std::max(ttValue - 2 * depth / ONE_PLY, -VALUE_MATE); + Depth d = (depth / (2 * ONE_PLY)) * ONE_PLY; + ss->excludedMove = move; + value = search(pos, ss, rBeta - 1, rBeta, d, cutNode, true); + ss->excludedMove = MOVE_NONE; + + if (value < rBeta) + extension = ONE_PLY; + } + else if ( givesCheck + && !moveCountPruning + && pos.see_ge(move)) + extension = ONE_PLY; + + // Calculate new depth for this move + newDepth = depth - ONE_PLY + extension; + + // Step 13. Pruning at shallow depth + if ( !rootNode + && pos.non_pawn_material(pos.side_to_move()) + && bestValue > VALUE_MATED_IN_MAX_PLY) + { + if ( !captureOrPromotion + && !givesCheck + && (!pos.advanced_pawn_push(move) || pos.non_pawn_material() >= Value(5000))) + { + // Move count based pruning + if (moveCountPruning) + { + skipQuiets = true; + continue; + } + + // Reduced depth of the next LMR search + int lmrDepth = std::max(newDepth - reduction(improving, depth, moveCount), DEPTH_ZERO) / ONE_PLY; + + // Countermoves based pruning + if ( lmrDepth < 3 + && (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold + && (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold) + continue; + + // Futility pruning: parent node + if ( lmrDepth < 7 + && !inCheck + && ss->staticEval + 256 + 200 * lmrDepth <= alpha) + continue; + + // Prune moves with negative SEE + if ( lmrDepth < 8 + && !pos.see_ge(move, Value(-35 * lmrDepth * lmrDepth))) + continue; + } + else if ( depth < 7 * ONE_PLY + && !extension + && !pos.see_ge(move, -PawnValueEg * (depth / ONE_PLY))) + continue; + } + + // Speculative prefetch as early as possible + prefetch(TT.first_entry(pos.key_after(move))); + + // Check for legality just before making the move + if (!rootNode && !pos.legal(move)) + { + ss->moveCount = --moveCount; + continue; + } + + if (move == ttMove && captureOrPromotion) + ttCapture = true; + + // Update the current move (this must be done after singular extension search) + ss->currentMove = move; + ss->contHistory = &thisThread->contHistory[movedPiece][to_sq(move)]; + + // Step 14. Make the move + pos.do_move(move, st, givesCheck); + + // Step 15. Reduced depth search (LMR). If the move fails high it will be + // re-searched at full depth. + if ( depth >= 3 * ONE_PLY + && moveCount > 1 + && (!captureOrPromotion || moveCountPruning)) + { + Depth r = reduction(improving, depth, moveCount); + + if (captureOrPromotion) + r -= r ? ONE_PLY : DEPTH_ZERO; + else + { + // Decrease reduction if opponent's move count is high + if ((ss-1)->moveCount > 15) + r -= ONE_PLY; + + // Decrease reduction for exact PV nodes + if (pvExact) + r -= ONE_PLY; + + // Increase reduction if ttMove is a capture + if (ttCapture) + r += ONE_PLY; + + // Increase reduction for cut nodes + if (cutNode) + r += 2 * ONE_PLY; + + // Decrease reduction for moves that escape a capture. Filter out + // castling moves, because they are coded as "king captures rook" and + // hence break make_move(). + else if ( type_of(move) == NORMAL + && !pos.see_ge(make_move(to_sq(move), from_sq(move)))) + r -= 2 * ONE_PLY; + + ss->statScore = thisThread->mainHistory[~pos.side_to_move()][from_to(move)] + + (*contHist[0])[movedPiece][to_sq(move)] + + (*contHist[1])[movedPiece][to_sq(move)] + + (*contHist[3])[movedPiece][to_sq(move)] + - 4000; + + // Decrease/increase reduction by comparing opponent's stat score + if (ss->statScore >= 0 && (ss-1)->statScore < 0) + r -= ONE_PLY; + + else if ((ss-1)->statScore >= 0 && ss->statScore < 0) + r += ONE_PLY; + + // Decrease/increase reduction for moves with a good/bad history + r = std::max(DEPTH_ZERO, (r / ONE_PLY - ss->statScore / 20000) * ONE_PLY); + } + + Depth d = std::max(newDepth - r, ONE_PLY); + + value = -search(pos, ss+1, -(alpha+1), -alpha, d, true, false); + + doFullDepthSearch = (value > alpha && d != newDepth); + } + else + doFullDepthSearch = !PvNode || moveCount > 1; + + // Step 16. Full depth search when LMR is skipped or fails high + if (doFullDepthSearch) + value = newDepth < ONE_PLY ? + givesCheck ? -qsearch(pos, ss+1, -(alpha+1), -alpha) + : -qsearch(pos, ss+1, -(alpha+1), -alpha) + : - search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode, false); + + // For PV nodes only, do a full PV search on the first move or after a fail + // high (in the latter case search only if value < beta), otherwise let the + // parent node fail low with value <= alpha and try another move. + if (PvNode && (moveCount == 1 || (value > alpha && (rootNode || value < beta)))) + { + (ss+1)->pv = pv; + (ss+1)->pv[0] = MOVE_NONE; + + value = newDepth < ONE_PLY ? + givesCheck ? -qsearch(pos, ss+1, -beta, -alpha) + : -qsearch(pos, ss+1, -beta, -alpha) + : - search(pos, ss+1, -beta, -alpha, newDepth, false, false); + } + + // Step 17. Undo move + pos.undo_move(move); + + assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); + + // Step 18. Check for a new best move + // Finished searching the move. If a stop occurred, the return value of + // the search cannot be trusted, and we return immediately without + // updating best move, PV and TT. + if (Threads.stop.load(std::memory_order_relaxed)) + return VALUE_ZERO; + + if (rootNode) + { + RootMove& rm = *std::find(thisThread->rootMoves.begin(), + thisThread->rootMoves.end(), move); + + // PV move or new best move ? + if (moveCount == 1 || value > alpha) + { + rm.score = value; + rm.selDepth = thisThread->selDepth; + rm.pv.resize(1); + + assert((ss+1)->pv); + + for (Move* m = (ss+1)->pv; *m != MOVE_NONE; ++m) + rm.pv.push_back(*m); + + // We record how often the best move has been changed in each + // iteration. This information is used for time management: When + // the best move changes frequently, we allocate some more time. + if (moveCount > 1 && thisThread == Threads.main()) + ++static_cast(thisThread)->bestMoveChanges; + } + else + // All other moves but the PV are set to the lowest value: this + // is not a problem when sorting because the sort is stable and the + // move position in the list is preserved - just the PV is pushed up. + rm.score = -VALUE_INFINITE; + } + + if (value > bestValue) + { + bestValue = value; + + if (value > alpha) + { + bestMove = move; + + if (PvNode && !rootNode) // Update pv even in fail-high case + update_pv(ss->pv, move, (ss+1)->pv); + + if (PvNode && value < beta) // Update alpha! Always alpha < beta + alpha = value; + else + { + assert(value >= beta); // Fail high + break; + } + } + } + + if (!captureOrPromotion && move != bestMove && quietCount < 64) + quietsSearched[quietCount++] = move; + else if (captureOrPromotion && move != bestMove && captureCount < 32) + capturesSearched[captureCount++] = move; + } + + // The following condition would detect a stop only after move loop has been + // completed. But in this case bestValue is valid because we have fully + // searched our subtree, and we can anyhow save the result in TT. + /* + if (Threads.stop) + return VALUE_DRAW; + */ + + // Step 20. Check for mate and stalemate + // All legal moves have been searched and if there are no legal moves, it + // must be a mate or a stalemate. If we are in a singular extension search then + // return a fail low score. + + assert(moveCount || !inCheck || excludedMove || !MoveList(pos).size()); + + if (!moveCount) + bestValue = excludedMove ? alpha + : inCheck ? mated_in(ss->ply) : VALUE_DRAW; + else if (bestMove) + { + // Quiet best move: update move sorting heuristics + if (!pos.capture_or_promotion(bestMove)) + update_stats(pos, ss, bestMove, quietsSearched, quietCount, stat_bonus(depth)); + else + update_capture_stats(pos, bestMove, capturesSearched, captureCount, stat_bonus(depth)); + + // Extra penalty for a quiet TT move in previous ply when it gets refuted + if ((ss-1)->moveCount == 1 && !pos.captured_piece()) + update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY)); + } + // Bonus for prior countermove that caused the fail low + else if ( depth >= 3 * ONE_PLY + && !pos.captured_piece() + && is_ok((ss-1)->currentMove)) + update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth)); + + if (PvNode) + bestValue = std::min(bestValue, maxValue); + + if (!excludedMove) + tte->save(posKey, value_to_tt(bestValue, ss->ply), + bestValue >= beta ? BOUND_LOWER : + PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER, + depth, bestMove, ss->staticEval, TT.generation()); + + assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); + + return bestValue; + } + + + // qsearch() is the quiescence search function, which is called by the main + // search function with depth zero, or recursively with depth less than ONE_PLY. + + template + Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { + + const bool PvNode = NT == PV; + + assert(InCheck == bool(pos.checkers())); + assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE); + assert(PvNode || (alpha == beta - 1)); + assert(depth <= DEPTH_ZERO); + assert(depth / ONE_PLY * ONE_PLY == depth); + + Move pv[MAX_PLY+1]; + StateInfo st; + TTEntry* tte; + Key posKey; + Move ttMove, move, bestMove; + Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha; + bool ttHit, givesCheck, evasionPrunable; + Depth ttDepth; + int moveCount; + + if (PvNode) + { + oldAlpha = alpha; // To flag BOUND_EXACT when eval above alpha and no available moves + (ss+1)->pv = pv; + ss->pv[0] = MOVE_NONE; + } + + ss->currentMove = bestMove = MOVE_NONE; + (ss+1)->ply = ss->ply + 1; + moveCount = 0; + + // Check for an instant draw or if the maximum ply has been reached + if (pos.is_draw(ss->ply) || ss->ply >= MAX_PLY) + return ss->ply >= MAX_PLY && !InCheck ? evaluate(pos) : VALUE_DRAW; + + assert(0 <= ss->ply && ss->ply < MAX_PLY); + + // Decide whether or not to include checks: this fixes also the type of + // TT entry depth that we are going to use. Note that in qsearch we use + // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS. + ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS + : DEPTH_QS_NO_CHECKS; + // Transposition table lookup + posKey = pos.key(); + tte = TT.probe(posKey, ttHit); + ttMove = ttHit ? tte->move() : MOVE_NONE; + ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE; + + if ( !PvNode + && ttHit + && tte->depth() >= ttDepth + && ttValue != VALUE_NONE // Only in case of TT access race + && (ttValue >= beta ? (tte->bound() & BOUND_LOWER) + : (tte->bound() & BOUND_UPPER))) + return ttValue; + + // Evaluate the position statically + if (InCheck) + { + ss->staticEval = VALUE_NONE; + bestValue = futilityBase = -VALUE_INFINITE; + } + else + { + if (ttHit) + { + // Never assume anything on values stored in TT + if ((ss->staticEval = bestValue = tte->eval()) == VALUE_NONE) + ss->staticEval = bestValue = evaluate(pos); + + // Can ttValue be used as a better position evaluation? + if ( ttValue != VALUE_NONE + && (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER))) + bestValue = ttValue; + } + else + ss->staticEval = bestValue = + (ss-1)->currentMove != MOVE_NULL ? evaluate(pos) + : -(ss-1)->staticEval + 2 * Eval::Tempo; + + // Stand pat. Return immediately if static value is at least beta + if (bestValue >= beta) + { + if (!ttHit) + tte->save(posKey, value_to_tt(bestValue, ss->ply), BOUND_LOWER, + DEPTH_NONE, MOVE_NONE, ss->staticEval, TT.generation()); + + return bestValue; + } + + if (PvNode && bestValue > alpha) + alpha = bestValue; + + futilityBase = bestValue + 128; + } + + // Initialize a MovePicker object for the current position, and prepare + // to search the moves. Because the depth is <= 0 here, only captures, + // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will + // be generated. + MovePicker mp(pos, ttMove, depth, &pos.this_thread()->mainHistory, &pos.this_thread()->captureHistory, to_sq((ss-1)->currentMove)); + + // Loop through the moves until no moves remain or a beta cutoff occurs + while ((move = mp.next_move()) != MOVE_NONE) + { + assert(is_ok(move)); + + givesCheck = type_of(move) == NORMAL && !pos.discovered_check_candidates() + ? pos.check_squares(type_of(pos.moved_piece(move))) & to_sq(move) + : pos.gives_check(move); + + moveCount++; + + // Futility pruning + if ( !InCheck + && !givesCheck + && futilityBase > -VALUE_KNOWN_WIN + && !pos.advanced_pawn_push(move)) + { + assert(type_of(move) != ENPASSANT); // Due to !pos.advanced_pawn_push + + futilityValue = futilityBase + PieceValue[EG][pos.piece_on(to_sq(move))]; + + if (futilityValue <= alpha) + { + bestValue = std::max(bestValue, futilityValue); + continue; + } + + if (futilityBase <= alpha && !pos.see_ge(move, VALUE_ZERO + 1)) + { + bestValue = std::max(bestValue, futilityBase); + continue; + } + } + + // Detect non-capture evasions that are candidates to be pruned + evasionPrunable = InCheck + && (depth != DEPTH_ZERO || moveCount > 2) + && bestValue > VALUE_MATED_IN_MAX_PLY + && !pos.capture(move); + + // Don't search moves with negative SEE values + if ( (!InCheck || evasionPrunable) + && !pos.see_ge(move)) + continue; + + // Speculative prefetch as early as possible + prefetch(TT.first_entry(pos.key_after(move))); + + // Check for legality just before making the move + if (!pos.legal(move)) + { + moveCount--; + continue; + } + + ss->currentMove = move; + + // Make and search the move + pos.do_move(move, st, givesCheck); + value = givesCheck ? -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY) + : -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY); + pos.undo_move(move); + + assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); + + // Check for a new best move + if (value > bestValue) + { + bestValue = value; + + if (value > alpha) + { + if (PvNode) // Update pv even in fail-high case + update_pv(ss->pv, move, (ss+1)->pv); + + if (PvNode && value < beta) // Update alpha here! + { + alpha = value; + bestMove = move; + } + else // Fail high + { + tte->save(posKey, value_to_tt(value, ss->ply), BOUND_LOWER, + ttDepth, move, ss->staticEval, TT.generation()); + + return value; + } + } + } + } + + // All legal moves have been searched. A special case: If we're in check + // and no legal moves were found, it is checkmate. + if (InCheck && bestValue == -VALUE_INFINITE) + return mated_in(ss->ply); // Plies to mate from the root + + tte->save(posKey, value_to_tt(bestValue, ss->ply), + PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER, + ttDepth, bestMove, ss->staticEval, TT.generation()); + + assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); + + return bestValue; + } + + + // value_to_tt() adjusts a mate score from "plies to mate from the root" to + // "plies to mate from the current position". Non-mate scores are unchanged. + // The function is called before storing a value in the transposition table. + + Value value_to_tt(Value v, int ply) { + + assert(v != VALUE_NONE); + + return v >= VALUE_MATE_IN_MAX_PLY ? v + ply + : v <= VALUE_MATED_IN_MAX_PLY ? v - ply : v; + } + + + // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score + // from the transposition table (which refers to the plies to mate/be mated + // from current position) to "plies to mate/be mated from the root". + + Value value_from_tt(Value v, int ply) { + + return v == VALUE_NONE ? VALUE_NONE + : v >= VALUE_MATE_IN_MAX_PLY ? v - ply + : v <= VALUE_MATED_IN_MAX_PLY ? v + ply : v; + } + + + // update_pv() adds current move and appends child pv[] + + void update_pv(Move* pv, Move move, Move* childPv) { + + for (*pv++ = move; childPv && *childPv != MOVE_NONE; ) + *pv++ = *childPv++; + *pv = MOVE_NONE; + } + + + // update_continuation_histories() updates histories of the move pairs formed + // by moves at ply -1, -2, and -4 with current move. + + void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus) { + + for (int i : {1, 2, 4}) + if (is_ok((ss-i)->currentMove)) + (ss-i)->contHistory->update(pc, to, bonus); + } + + + // update_capture_stats() updates move sorting heuristics when a new capture best move is found + + void update_capture_stats(const Position& pos, Move move, + Move* captures, int captureCnt, int bonus) { + + CapturePieceToHistory& captureHistory = pos.this_thread()->captureHistory; + Piece moved_piece = pos.moved_piece(move); + PieceType captured = type_of(pos.piece_on(to_sq(move))); + captureHistory.update(moved_piece, to_sq(move), captured, bonus); + + // Decrease all the other played capture moves + for (int i = 0; i < captureCnt; ++i) + { + moved_piece = pos.moved_piece(captures[i]); + captured = type_of(pos.piece_on(to_sq(captures[i]))); + captureHistory.update(moved_piece, to_sq(captures[i]), captured, -bonus); + } + } + + + // update_stats() updates move sorting heuristics when a new quiet best move is found + + void update_stats(const Position& pos, Stack* ss, Move move, + Move* quiets, int quietsCnt, int bonus) { + + if (ss->killers[0] != move) + { + ss->killers[1] = ss->killers[0]; + ss->killers[0] = move; + } + + Color c = pos.side_to_move(); + Thread* thisThread = pos.this_thread(); + thisThread->mainHistory.update(c, move, bonus); + update_continuation_histories(ss, pos.moved_piece(move), to_sq(move), bonus); + + if (is_ok((ss-1)->currentMove)) + { + Square prevSq = to_sq((ss-1)->currentMove); + thisThread->counterMoves[pos.piece_on(prevSq)][prevSq] = move; + } + + // Decrease all the other played quiet moves + for (int i = 0; i < quietsCnt; ++i) + { + thisThread->mainHistory.update(c, quiets[i], -bonus); + update_continuation_histories(ss, pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); + } + } + + + // Is the PV leading to a draw position? Assumes all pv moves are legal + bool pv_is_draw(Position& pos) { + + StateInfo st[MAX_PLY]; + auto& pv = pos.this_thread()->rootMoves[0].pv; + + for (size_t i = 0; i < pv.size(); ++i) + pos.do_move(pv[i], st[i]); + + bool isDraw = pos.is_draw(pv.size()); + + for (size_t i = pv.size(); i > 0; --i) + pos.undo_move(pv[i-1]); + + return isDraw; + } + + + // When playing with strength handicap, choose best move among a set of RootMoves + // using a statistical rule dependent on 'level'. Idea by Heinz van Saanen. + + Move Skill::pick_best(size_t multiPV) { + + const RootMoves& rootMoves = Threads.main()->rootMoves; + static PRNG rng(now()); // PRNG sequence should be non-deterministic + + // RootMoves are already sorted by score in descending order + Value topScore = rootMoves[0].score; + int delta = std::min(topScore - rootMoves[multiPV - 1].score, PawnValueMg); + int weakness = 120 - 2 * level; + int maxScore = -VALUE_INFINITE; + + // Choose best move. For each move score we add two terms, both dependent on + // weakness. One is deterministic and bigger for weaker levels, and one is + // random. Then we choose the move with the resulting highest score. + for (size_t i = 0; i < multiPV; ++i) + { + // This is our magic formula + int push = ( weakness * int(topScore - rootMoves[i].score) + + delta * (rng.rand() % weakness)) / 128; + + if (rootMoves[i].score + push >= maxScore) + { + maxScore = rootMoves[i].score + push; + best = rootMoves[i].pv[0]; + } + } + + return best; + } + +} // namespace + + // check_time() is used to print debug info and, more importantly, to detect + // when we are out of available time and thus stop the search. + + void MainThread::check_time() { + + if (--callsCnt > 0) + return; + + // At low node count increase the checking rate to about 0.1% of nodes + // otherwise use a default value. + callsCnt = Limits.nodes ? std::min(4096, int(Limits.nodes / 1024)) : 4096; + + static TimePoint lastInfoTime = now(); + + int elapsed = Time.elapsed(); + TimePoint tick = Limits.startTime + elapsed; + + if (tick - lastInfoTime >= 1000) + { + lastInfoTime = tick; + dbg_print(); + } + + // An engine may not stop pondering until told so by the GUI + if (Threads.ponder) + return; + + if ( (Limits.use_time_management() && elapsed > Time.maximum() - 10) + || (Limits.movetime && elapsed >= Limits.movetime) + || (Limits.nodes && Threads.nodes_searched() >= (uint64_t)Limits.nodes)) + Threads.stop = true; + } + + +/// UCI::pv() formats PV information according to the UCI protocol. UCI requires +/// that all (if any) unsearched PV lines are sent using a previous search score. + +string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { + + std::stringstream ss; + int elapsed = Time.elapsed() + 1; + const RootMoves& rootMoves = pos.this_thread()->rootMoves; + size_t PVIdx = pos.this_thread()->PVIdx; + size_t multiPV = std::min((size_t)Options["MultiPV"], rootMoves.size()); + uint64_t nodesSearched = Threads.nodes_searched(); + uint64_t tbHits = Threads.tb_hits() + (TB::RootInTB ? rootMoves.size() : 0); + + for (size_t i = 0; i < multiPV; ++i) + { + bool updated = (i <= PVIdx && rootMoves[i].score != -VALUE_INFINITE); + + if (depth == ONE_PLY && !updated) + continue; + + Depth d = updated ? depth : depth - ONE_PLY; + Value v = updated ? rootMoves[i].score : rootMoves[i].previousScore; + + bool tb = TB::RootInTB && abs(v) < VALUE_MATE - MAX_PLY; + v = tb ? TB::Score : v; + + if (ss.rdbuf()->in_avail()) // Not at first line + ss << "\n"; + + ss << "info" + << " depth " << d / ONE_PLY + << " seldepth " << rootMoves[i].selDepth + << " multipv " << i + 1 + << " score " << UCI::value(v); + + if (!tb && i == PVIdx) + ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : ""); + + ss << " nodes " << nodesSearched + << " nps " << nodesSearched * 1000 / elapsed; + + if (elapsed > 1000) // Earlier makes little sense + ss << " hashfull " << TT.hashfull(); + + ss << " tbhits " << tbHits + << " time " << elapsed + << " pv"; + + for (Move m : rootMoves[i].pv) + ss << " " << UCI::move(m, pos.is_chess960()); + } + + return ss.str(); +} + + +/// RootMove::extract_ponder_from_tt() is called in case we have no ponder move +/// before exiting the search, for instance, in case we stop the search during a +/// fail high at root. We try hard to have a ponder move to return to the GUI, +/// otherwise in case of 'ponder on' we have nothing to think on. + +bool RootMove::extract_ponder_from_tt(Position& pos) { + + StateInfo st; + bool ttHit; + + assert(pv.size() == 1); + + if (!pv[0]) + return false; + + pos.do_move(pv[0], st); + TTEntry* tte = TT.probe(pos.key(), ttHit); + + if (ttHit) + { + Move m = tte->move(); // Local copy to be SMP safe + if (MoveList(pos).contains(m)) + pv.push_back(m); + } + + pos.undo_move(pv[0]); + return pv.size() > 1; +} + +void Tablebases::filter_root_moves(Position& pos, Search::RootMoves& rootMoves) { + + RootInTB = false; + UseRule50 = Options["Syzygy50MoveRule"]; + ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY; + Cardinality = Options["SyzygyProbeLimit"]; + + // Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality + if (Cardinality > MaxCardinality) + { + Cardinality = MaxCardinality; + ProbeDepth = DEPTH_ZERO; + } + + if (Cardinality < popcount(pos.pieces()) || pos.can_castle(ANY_CASTLING)) + return; + + // Don't filter any moves if the user requested analysis on multiple + if (Options["MultiPV"] != 1) + return; + + // If the current root position is in the tablebases, then RootMoves + // contains only moves that preserve the draw or the win. + RootInTB = root_probe(pos, rootMoves, TB::Score); + + if (RootInTB) + Cardinality = 0; // Do not probe tablebases during the search + + else // If DTZ tables are missing, use WDL tables as a fallback + { + // Filter out moves that do not preserve the draw or the win. + RootInTB = root_probe_wdl(pos, rootMoves, TB::Score); + + // Only probe during search if winning + if (RootInTB && TB::Score <= VALUE_DRAW) + Cardinality = 0; + } + + if (RootInTB && !UseRule50) + TB::Score = TB::Score > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1 + : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1 + : VALUE_DRAW; + + // Since root_probe() and root_probe_wdl() dirty the root move scores, + // we reset them to -VALUE_INFINITE + for (RootMove& rm : rootMoves) + rm.score = -VALUE_INFINITE; +} diff --git a/src/search.h b/src/search.h new file mode 100644 index 0000000..1274b96 --- /dev/null +++ b/src/search.h @@ -0,0 +1,106 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef SEARCH_H_INCLUDED +#define SEARCH_H_INCLUDED + +#include + +#include "misc.h" +#include "movepick.h" +#include "types.h" + +class Position; + +namespace Search { + +/// Threshold used for countermoves based pruning +const int CounterMovePruneThreshold = 0; + + +/// Stack struct keeps track of the information we need to remember from nodes +/// shallower and deeper in the tree during the search. Each search thread has +/// its own array of Stack objects, indexed by the current ply. + +struct Stack { + Move* pv; + PieceToHistory* contHistory; + int ply; + Move currentMove; + Move excludedMove; + Move killers[2]; + Value staticEval; + int statScore; + int moveCount; +}; + + +/// RootMove struct is used for moves at the root of the tree. For each root move +/// we store a score and a PV (really a refutation in the case of moves which +/// fail low). Score is normally set at -VALUE_INFINITE for all non-pv moves. + +struct RootMove { + + explicit RootMove(Move m) : pv(1, m) {} + bool extract_ponder_from_tt(Position& pos); + bool operator==(const Move& m) const { return pv[0] == m; } + bool operator<(const RootMove& m) const { // Sort in descending order + return m.score != score ? m.score < score + : m.previousScore < previousScore; + } + + Value score = -VALUE_INFINITE; + Value previousScore = -VALUE_INFINITE; + int selDepth = 0; + std::vector pv; +}; + +typedef std::vector RootMoves; + + +/// LimitsType struct stores information sent by GUI about available time to +/// search the current move, maximum depth/time, or if we are in analysis mode. + +struct LimitsType { + + LimitsType() { // Init explicitly due to broken value-initialization of non POD in MSVC + nodes = time[WHITE] = time[BLACK] = inc[WHITE] = inc[BLACK] = + npmsec = movestogo = depth = movetime = mate = perft = infinite = 0; + } + + bool use_time_management() const { + return !(mate | movetime | depth | nodes | perft | infinite); + } + + std::vector searchmoves; + int time[COLOR_NB], inc[COLOR_NB], npmsec, movestogo, depth, + movetime, mate, perft, infinite; + int64_t nodes; + TimePoint startTime; +}; + +extern LimitsType Limits; + +void init(); +void clear(); + +} // namespace Search + +#endif // #ifndef SEARCH_H_INCLUDED diff --git a/src/syzygy/tbprobe.cpp b/src/syzygy/tbprobe.cpp new file mode 100644 index 0000000..b50275e --- /dev/null +++ b/src/syzygy/tbprobe.cpp @@ -0,0 +1,1702 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (c) 2013 Ronald de Man + Copyright (C) 2016-2018 Marco Costalba, Lucas Braesch + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include +#include // For std::memset +#include +#include +#include +#include +#include +#include + +#include "../bitboard.h" +#include "../movegen.h" +#include "../position.h" +#include "../search.h" +#include "../thread_win32.h" +#include "../types.h" + +#include "tbprobe.h" + +#ifndef _WIN32 +#include +#include +#include +#include +#else +#define WIN32_LEAN_AND_MEAN +#define NOMINMAX +#include +#endif + +using namespace Tablebases; + +int Tablebases::MaxCardinality; + +namespace { + +// Each table has a set of flags: all of them refer to DTZ tables, the last one to WDL tables +enum TBFlag { STM = 1, Mapped = 2, WinPlies = 4, LossPlies = 8, SingleValue = 128 }; + +inline WDLScore operator-(WDLScore d) { return WDLScore(-int(d)); } +inline Square operator^=(Square& s, int i) { return s = Square(int(s) ^ i); } +inline Square operator^(Square s, int i) { return Square(int(s) ^ i); } + +// DTZ tables don't store valid scores for moves that reset the rule50 counter +// like captures and pawn moves but we can easily recover the correct dtz of the +// previous move if we know the position's WDL score. +int dtz_before_zeroing(WDLScore wdl) { + return wdl == WDLWin ? 1 : + wdl == WDLCursedWin ? 101 : + wdl == WDLBlessedLoss ? -101 : + wdl == WDLLoss ? -1 : 0; +} + +// Return the sign of a number (-1, 0, 1) +template int sign_of(T val) { + return (T(0) < val) - (val < T(0)); +} + +// Numbers in little endian used by sparseIndex[] to point into blockLength[] +struct SparseEntry { + char block[4]; // Number of block + char offset[2]; // Offset within the block +}; + +static_assert(sizeof(SparseEntry) == 6, "SparseEntry must be 6 bytes"); + +typedef uint16_t Sym; // Huffman symbol + +struct LR { + enum Side { Left, Right, Value }; + + uint8_t lr[3]; // The first 12 bits is the left-hand symbol, the second 12 + // bits is the right-hand symbol. If symbol has length 1, + // then the first byte is the stored value. + template + Sym get() { + return S == Left ? ((lr[1] & 0xF) << 8) | lr[0] : + S == Right ? (lr[2] << 4) | (lr[1] >> 4) : + S == Value ? lr[0] : (assert(false), Sym(-1)); + } +}; + +static_assert(sizeof(LR) == 3, "LR tree entry must be 3 bytes"); + +const int TBPIECES = 6; + +struct PairsData { + int flags; + size_t sizeofBlock; // Block size in bytes + size_t span; // About every span values there is a SparseIndex[] entry + int blocksNum; // Number of blocks in the TB file + int maxSymLen; // Maximum length in bits of the Huffman symbols + int minSymLen; // Minimum length in bits of the Huffman symbols + Sym* lowestSym; // lowestSym[l] is the symbol of length l with the lowest value + LR* btree; // btree[sym] stores the left and right symbols that expand sym + uint16_t* blockLength; // Number of stored positions (minus one) for each block: 1..65536 + int blockLengthSize; // Size of blockLength[] table: padded so it's bigger than blocksNum + SparseEntry* sparseIndex; // Partial indices into blockLength[] + size_t sparseIndexSize; // Size of SparseIndex[] table + uint8_t* data; // Start of Huffman compressed data + std::vector base64; // base64[l - min_sym_len] is the 64bit-padded lowest symbol of length l + std::vector symlen; // Number of values (-1) represented by a given Huffman symbol: 1..256 + Piece pieces[TBPIECES]; // Position pieces: the order of pieces defines the groups + uint64_t groupIdx[TBPIECES+1]; // Start index used for the encoding of the group's pieces + int groupLen[TBPIECES+1]; // Number of pieces in a given group: KRKN -> (3, 1) +}; + +// Helper struct to avoid manually defining entry copy constructor as we +// should because the default one is not compatible with std::atomic_bool. +struct Atomic { + Atomic() = default; + Atomic(const Atomic& e) { ready = e.ready.load(); } // MSVC 2013 wants assignment within body + std::atomic_bool ready; +}; + +// We define types for the different parts of the WDLEntry and DTZEntry with +// corresponding specializations for pieces or pawns. + +struct WDLEntryPiece { + PairsData* precomp; +}; + +struct WDLEntryPawn { + uint8_t pawnCount[2]; // [Lead color / other color] + WDLEntryPiece file[2][4]; // [wtm / btm][FILE_A..FILE_D] +}; + +struct DTZEntryPiece { + PairsData* precomp; + uint16_t map_idx[4]; // WDLWin, WDLLoss, WDLCursedWin, WDLBlessedLoss + uint8_t* map; +}; + +struct DTZEntryPawn { + uint8_t pawnCount[2]; + DTZEntryPiece file[4]; + uint8_t* map; +}; + +struct TBEntry : public Atomic { + void* baseAddress; + uint64_t mapping; + Key key; + Key key2; + int pieceCount; + bool hasPawns; + bool hasUniquePieces; +}; + +// Now the main types: WDLEntry and DTZEntry +struct WDLEntry : public TBEntry { + WDLEntry(const std::string& code); + ~WDLEntry(); + union { + WDLEntryPiece pieceTable[2]; // [wtm / btm] + WDLEntryPawn pawnTable; + }; +}; + +struct DTZEntry : public TBEntry { + DTZEntry(const WDLEntry& wdl); + ~DTZEntry(); + union { + DTZEntryPiece pieceTable; + DTZEntryPawn pawnTable; + }; +}; + +typedef decltype(WDLEntry::pieceTable) WDLPieceTable; +typedef decltype(DTZEntry::pieceTable) DTZPieceTable; +typedef decltype(WDLEntry::pawnTable ) WDLPawnTable; +typedef decltype(DTZEntry::pawnTable ) DTZPawnTable; + +auto item(WDLPieceTable& e, int stm, int ) -> decltype(e[stm])& { return e[stm]; } +auto item(DTZPieceTable& e, int , int ) -> decltype(e)& { return e; } +auto item(WDLPawnTable& e, int stm, int f) -> decltype(e.file[stm][f])& { return e.file[stm][f]; } +auto item(DTZPawnTable& e, int , int f) -> decltype(e.file[f])& { return e.file[f]; } + +template struct Ret { typedef int type; }; +template<> struct Ret { typedef WDLScore type; }; + +int MapPawns[SQUARE_NB]; +int MapB1H1H7[SQUARE_NB]; +int MapA1D1D4[SQUARE_NB]; +int MapKK[10][SQUARE_NB]; // [MapA1D1D4][SQUARE_NB] + +// Comparison function to sort leading pawns in ascending MapPawns[] order +bool pawns_comp(Square i, Square j) { return MapPawns[i] < MapPawns[j]; } +int off_A1H8(Square sq) { return int(rank_of(sq)) - file_of(sq); } + +const Value WDL_to_value[] = { + -VALUE_MATE + MAX_PLY + 1, + VALUE_DRAW - 2, + VALUE_DRAW, + VALUE_DRAW + 2, + VALUE_MATE - MAX_PLY - 1 +}; + +const std::string PieceToChar = " PNBRQK pnbrqk"; + +int Binomial[6][SQUARE_NB]; // [k][n] k elements from a set of n elements +int LeadPawnIdx[5][SQUARE_NB]; // [leadPawnsCnt][SQUARE_NB] +int LeadPawnsSize[5][4]; // [leadPawnsCnt][FILE_A..FILE_D] + +enum { BigEndian, LittleEndian }; + +template +inline void swap_byte(T& x) +{ + char tmp, *c = (char*)&x; + for (int i = 0; i < Half; ++i) + tmp = c[i], c[i] = c[End - i], c[End - i] = tmp; +} +template<> inline void swap_byte(uint8_t&) {} + +template T number(void* addr) +{ + const union { uint32_t i; char c[4]; } Le = { 0x01020304 }; + const bool IsLittleEndian = (Le.c[0] == 4); + + T v; + + if ((uintptr_t)addr & (alignof(T) - 1)) // Unaligned pointer (very rare) + std::memcpy(&v, addr, sizeof(T)); + else + v = *((T*)addr); + + if (LE != IsLittleEndian) + swap_byte(v); + return v; +} + +class HashTable { + + typedef std::pair EntryPair; + typedef std::pair Entry; + + static const int TBHASHBITS = 10; + static const int HSHMAX = 5; + + Entry hashTable[1 << TBHASHBITS][HSHMAX]; + + std::deque wdlTable; + std::deque dtzTable; + + void insert(Key key, WDLEntry* wdl, DTZEntry* dtz) { + Entry* entry = hashTable[key >> (64 - TBHASHBITS)]; + + for (int i = 0; i < HSHMAX; ++i, ++entry) + if (!entry->second.first || entry->first == key) { + *entry = std::make_pair(key, std::make_pair(wdl, dtz)); + return; + } + + std::cerr << "HSHMAX too low!" << std::endl; + exit(1); + } + +public: + template::value ? 0 : 1> + E* get(Key key) { + Entry* entry = hashTable[key >> (64 - TBHASHBITS)]; + + for (int i = 0; i < HSHMAX; ++i, ++entry) + if (entry->first == key) + return std::get(entry->second); + + return nullptr; + } + + void clear() { + std::memset(hashTable, 0, sizeof(hashTable)); + wdlTable.clear(); + dtzTable.clear(); + } + size_t size() const { return wdlTable.size(); } + void insert(const std::vector& pieces); +}; + +HashTable EntryTable; + +class TBFile : public std::ifstream { + + std::string fname; + +public: + // Look for and open the file among the Paths directories where the .rtbw + // and .rtbz files can be found. Multiple directories are separated by ";" + // on Windows and by ":" on Unix-based operating systems. + // + // Example: + // C:\tb\wdl345;C:\tb\wdl6;D:\tb\dtz345;D:\tb\dtz6 + static std::string Paths; + + TBFile(const std::string& f) { + +#ifndef _WIN32 + const char SepChar = ':'; +#else + const char SepChar = ';'; +#endif + std::stringstream ss(Paths); + std::string path; + + while (std::getline(ss, path, SepChar)) { + fname = path + "/" + f; + std::ifstream::open(fname); + if (is_open()) + return; + } + } + + // Memory map the file and check it. File should be already open and will be + // closed after mapping. + uint8_t* map(void** baseAddress, uint64_t* mapping, const uint8_t* TB_MAGIC) { + + assert(is_open()); + + close(); // Need to re-open to get native file descriptor + +#ifndef _WIN32 + struct stat statbuf; + int fd = ::open(fname.c_str(), O_RDONLY); + + if (fd == -1) + return *baseAddress = nullptr, nullptr; + + fstat(fd, &statbuf); + *mapping = statbuf.st_size; + *baseAddress = mmap(nullptr, statbuf.st_size, PROT_READ, MAP_SHARED, fd, 0); + ::close(fd); + + if (*baseAddress == MAP_FAILED) { + std::cerr << "Could not mmap() " << fname << std::endl; + exit(1); + } +#else + HANDLE fd = CreateFile(fname.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr, + OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr); + + if (fd == INVALID_HANDLE_VALUE) + return *baseAddress = nullptr, nullptr; + + DWORD size_high; + DWORD size_low = GetFileSize(fd, &size_high); + HANDLE mmap = CreateFileMapping(fd, nullptr, PAGE_READONLY, size_high, size_low, nullptr); + CloseHandle(fd); + + if (!mmap) { + std::cerr << "CreateFileMapping() failed" << std::endl; + exit(1); + } + + *mapping = (uint64_t)mmap; + *baseAddress = MapViewOfFile(mmap, FILE_MAP_READ, 0, 0, 0); + + if (!*baseAddress) { + std::cerr << "MapViewOfFile() failed, name = " << fname + << ", error = " << GetLastError() << std::endl; + exit(1); + } +#endif + uint8_t* data = (uint8_t*)*baseAddress; + + if ( *data++ != *TB_MAGIC++ + || *data++ != *TB_MAGIC++ + || *data++ != *TB_MAGIC++ + || *data++ != *TB_MAGIC) { + std::cerr << "Corrupted table in file " << fname << std::endl; + unmap(*baseAddress, *mapping); + return *baseAddress = nullptr, nullptr; + } + + return data; + } + + static void unmap(void* baseAddress, uint64_t mapping) { + +#ifndef _WIN32 + munmap(baseAddress, mapping); +#else + UnmapViewOfFile(baseAddress); + CloseHandle((HANDLE)mapping); +#endif + } +}; + +std::string TBFile::Paths; + +WDLEntry::WDLEntry(const std::string& code) { + + StateInfo st; + Position pos; + + memset(this, 0, sizeof(WDLEntry)); + + ready = false; + key = pos.set(code, WHITE, &st).material_key(); + pieceCount = popcount(pos.pieces()); + hasPawns = pos.pieces(PAWN); + + for (Color c = WHITE; c <= BLACK; ++c) + for (PieceType pt = PAWN; pt < KING; ++pt) + if (popcount(pos.pieces(c, pt)) == 1) + hasUniquePieces = true; + + if (hasPawns) { + // Set the leading color. In case both sides have pawns the leading color + // is the side with less pawns because this leads to better compression. + bool c = !pos.count(BLACK) + || ( pos.count(WHITE) + && pos.count(BLACK) >= pos.count(WHITE)); + + pawnTable.pawnCount[0] = pos.count(c ? WHITE : BLACK); + pawnTable.pawnCount[1] = pos.count(c ? BLACK : WHITE); + } + + key2 = pos.set(code, BLACK, &st).material_key(); +} + +WDLEntry::~WDLEntry() { + + if (baseAddress) + TBFile::unmap(baseAddress, mapping); + + for (int i = 0; i < 2; ++i) + if (hasPawns) + for (File f = FILE_A; f <= FILE_D; ++f) + delete pawnTable.file[i][f].precomp; + else + delete pieceTable[i].precomp; +} + +DTZEntry::DTZEntry(const WDLEntry& wdl) { + + memset(this, 0, sizeof(DTZEntry)); + + ready = false; + key = wdl.key; + key2 = wdl.key2; + pieceCount = wdl.pieceCount; + hasPawns = wdl.hasPawns; + hasUniquePieces = wdl.hasUniquePieces; + + if (hasPawns) { + pawnTable.pawnCount[0] = wdl.pawnTable.pawnCount[0]; + pawnTable.pawnCount[1] = wdl.pawnTable.pawnCount[1]; + } +} + +DTZEntry::~DTZEntry() { + + if (baseAddress) + TBFile::unmap(baseAddress, mapping); + + if (hasPawns) + for (File f = FILE_A; f <= FILE_D; ++f) + delete pawnTable.file[f].precomp; + else + delete pieceTable.precomp; +} + +void HashTable::insert(const std::vector& pieces) { + + std::string code; + + for (PieceType pt : pieces) + code += PieceToChar[pt]; + + TBFile file(code.insert(code.find('K', 1), "v") + ".rtbw"); // KRK -> KRvK + + if (!file.is_open()) // Only WDL file is checked + return; + + file.close(); + + MaxCardinality = std::max((int)pieces.size(), MaxCardinality); + + wdlTable.emplace_back(code); + dtzTable.emplace_back(wdlTable.back()); + + insert(wdlTable.back().key , &wdlTable.back(), &dtzTable.back()); + insert(wdlTable.back().key2, &wdlTable.back(), &dtzTable.back()); +} + +// TB tables are compressed with canonical Huffman code. The compressed data is divided into +// blocks of size d->sizeofBlock, and each block stores a variable number of symbols. +// Each symbol represents either a WDL or a (remapped) DTZ value, or a pair of other symbols +// (recursively). If you keep expanding the symbols in a block, you end up with up to 65536 +// WDL or DTZ values. Each symbol represents up to 256 values and will correspond after +// Huffman coding to at least 1 bit. So a block of 32 bytes corresponds to at most +// 32 x 8 x 256 = 65536 values. This maximum is only reached for tables that consist mostly +// of draws or mostly of wins, but such tables are actually quite common. In principle, the +// blocks in WDL tables are 64 bytes long (and will be aligned on cache lines). But for +// mostly-draw or mostly-win tables this can leave many 64-byte blocks only half-filled, so +// in such cases blocks are 32 bytes long. The blocks of DTZ tables are up to 1024 bytes long. +// The generator picks the size that leads to the smallest table. The "book" of symbols and +// Huffman codes is the same for all blocks in the table. A non-symmetric pawnless TB file +// will have one table for wtm and one for btm, a TB file with pawns will have tables per +// file a,b,c,d also in this case one set for wtm and one for btm. +int decompress_pairs(PairsData* d, uint64_t idx) { + + // Special case where all table positions store the same value + if (d->flags & TBFlag::SingleValue) + return d->minSymLen; + + // First we need to locate the right block that stores the value at index "idx". + // Because each block n stores blockLength[n] + 1 values, the index i of the block + // that contains the value at position idx is: + // + // for (i = -1, sum = 0; sum <= idx; i++) + // sum += blockLength[i + 1] + 1; + // + // This can be slow, so we use SparseIndex[] populated with a set of SparseEntry that + // point to known indices into blockLength[]. Namely SparseIndex[k] is a SparseEntry + // that stores the blockLength[] index and the offset within that block of the value + // with index I(k), where: + // + // I(k) = k * d->span + d->span / 2 (1) + + // First step is to get the 'k' of the I(k) nearest to our idx, using definition (1) + uint32_t k = idx / d->span; + + // Then we read the corresponding SparseIndex[] entry + uint32_t block = number(&d->sparseIndex[k].block); + int offset = number(&d->sparseIndex[k].offset); + + // Now compute the difference idx - I(k). From definition of k we know that + // + // idx = k * d->span + idx % d->span (2) + // + // So from (1) and (2) we can compute idx - I(K): + int diff = idx % d->span - d->span / 2; + + // Sum the above to offset to find the offset corresponding to our idx + offset += diff; + + // Move to previous/next block, until we reach the correct block that contains idx, + // that is when 0 <= offset <= d->blockLength[block] + while (offset < 0) + offset += d->blockLength[--block] + 1; + + while (offset > d->blockLength[block]) + offset -= d->blockLength[block++] + 1; + + // Finally, we find the start address of our block of canonical Huffman symbols + uint32_t* ptr = (uint32_t*)(d->data + block * d->sizeofBlock); + + // Read the first 64 bits in our block, this is a (truncated) sequence of + // unknown number of symbols of unknown length but we know the first one + // is at the beginning of this 64 bits sequence. + uint64_t buf64 = number(ptr); ptr += 2; + int buf64Size = 64; + Sym sym; + + while (true) { + int len = 0; // This is the symbol length - d->min_sym_len + + // Now get the symbol length. For any symbol s64 of length l right-padded + // to 64 bits we know that d->base64[l-1] >= s64 >= d->base64[l] so we + // can find the symbol length iterating through base64[]. + while (buf64 < d->base64[len]) + ++len; + + // All the symbols of a given length are consecutive integers (numerical + // sequence property), so we can compute the offset of our symbol of + // length len, stored at the beginning of buf64. + sym = (buf64 - d->base64[len]) >> (64 - len - d->minSymLen); + + // Now add the value of the lowest symbol of length len to get our symbol + sym += number(&d->lowestSym[len]); + + // If our offset is within the number of values represented by symbol sym + // we are done... + if (offset < d->symlen[sym] + 1) + break; + + // ...otherwise update the offset and continue to iterate + offset -= d->symlen[sym] + 1; + len += d->minSymLen; // Get the real length + buf64 <<= len; // Consume the just processed symbol + buf64Size -= len; + + if (buf64Size <= 32) { // Refill the buffer + buf64Size += 32; + buf64 |= (uint64_t)number(ptr++) << (64 - buf64Size); + } + } + + // Ok, now we have our symbol that expands into d->symlen[sym] + 1 symbols. + // We binary-search for our value recursively expanding into the left and + // right child symbols until we reach a leaf node where symlen[sym] + 1 == 1 + // that will store the value we need. + while (d->symlen[sym]) { + + Sym left = d->btree[sym].get(); + + // If a symbol contains 36 sub-symbols (d->symlen[sym] + 1 = 36) and + // expands in a pair (d->symlen[left] = 23, d->symlen[right] = 11), then + // we know that, for instance the ten-th value (offset = 10) will be on + // the left side because in Recursive Pairing child symbols are adjacent. + if (offset < d->symlen[left] + 1) + sym = left; + else { + offset -= d->symlen[left] + 1; + sym = d->btree[sym].get(); + } + } + + return d->btree[sym].get(); +} + +bool check_dtz_stm(WDLEntry*, int, File) { return true; } + +bool check_dtz_stm(DTZEntry* entry, int stm, File f) { + + int flags = entry->hasPawns ? entry->pawnTable.file[f].precomp->flags + : entry->pieceTable.precomp->flags; + + return (flags & TBFlag::STM) == stm + || ((entry->key == entry->key2) && !entry->hasPawns); +} + +// DTZ scores are sorted by frequency of occurrence and then assigned the +// values 0, 1, 2, ... in order of decreasing frequency. This is done for each +// of the four WDLScore values. The mapping information necessary to reconstruct +// the original values is stored in the TB file and read during map[] init. +WDLScore map_score(WDLEntry*, File, int value, WDLScore) { return WDLScore(value - 2); } + +int map_score(DTZEntry* entry, File f, int value, WDLScore wdl) { + + const int WDLMap[] = { 1, 3, 0, 2, 0 }; + + int flags = entry->hasPawns ? entry->pawnTable.file[f].precomp->flags + : entry->pieceTable.precomp->flags; + + uint8_t* map = entry->hasPawns ? entry->pawnTable.map + : entry->pieceTable.map; + + uint16_t* idx = entry->hasPawns ? entry->pawnTable.file[f].map_idx + : entry->pieceTable.map_idx; + if (flags & TBFlag::Mapped) + value = map[idx[WDLMap[wdl + 2]] + value]; + + // DTZ tables store distance to zero in number of moves or plies. We + // want to return plies, so we have convert to plies when needed. + if ( (wdl == WDLWin && !(flags & TBFlag::WinPlies)) + || (wdl == WDLLoss && !(flags & TBFlag::LossPlies)) + || wdl == WDLCursedWin + || wdl == WDLBlessedLoss) + value *= 2; + + return value + 1; +} + +// Compute a unique index out of a position and use it to probe the TB file. To +// encode k pieces of same type and color, first sort the pieces by square in +// ascending order s1 <= s2 <= ... <= sk then compute the unique index as: +// +// idx = Binomial[1][s1] + Binomial[2][s2] + ... + Binomial[k][sk] +// +template::type> +T do_probe_table(const Position& pos, Entry* entry, WDLScore wdl, ProbeState* result) { + + const bool IsWDL = std::is_same::value; + + Square squares[TBPIECES]; + Piece pieces[TBPIECES]; + uint64_t idx; + int next = 0, size = 0, leadPawnsCnt = 0; + PairsData* d; + Bitboard b, leadPawns = 0; + File tbFile = FILE_A; + + // A given TB entry like KRK has associated two material keys: KRvk and Kvkr. + // If both sides have the same pieces keys are equal. In this case TB tables + // only store the 'white to move' case, so if the position to lookup has black + // to move, we need to switch the color and flip the squares before to lookup. + bool symmetricBlackToMove = (entry->key == entry->key2 && pos.side_to_move()); + + // TB files are calculated for white as stronger side. For instance we have + // KRvK, not KvKR. A position where stronger side is white will have its + // material key == entry->key, otherwise we have to switch the color and + // flip the squares before to lookup. + bool blackStronger = (pos.material_key() != entry->key); + + int flipColor = (symmetricBlackToMove || blackStronger) * 8; + int flipSquares = (symmetricBlackToMove || blackStronger) * 070; + int stm = (symmetricBlackToMove || blackStronger) ^ pos.side_to_move(); + + // For pawns, TB files store 4 separate tables according if leading pawn is on + // file a, b, c or d after reordering. The leading pawn is the one with maximum + // MapPawns[] value, that is the one most toward the edges and with lowest rank. + if (entry->hasPawns) { + + // In all the 4 tables, pawns are at the beginning of the piece sequence and + // their color is the reference one. So we just pick the first one. + Piece pc = Piece(item(entry->pawnTable, 0, 0).precomp->pieces[0] ^ flipColor); + + assert(type_of(pc) == PAWN); + + leadPawns = b = pos.pieces(color_of(pc), PAWN); + do + squares[size++] = pop_lsb(&b) ^ flipSquares; + while (b); + + leadPawnsCnt = size; + + std::swap(squares[0], *std::max_element(squares, squares + leadPawnsCnt, pawns_comp)); + + tbFile = file_of(squares[0]); + if (tbFile > FILE_D) + tbFile = file_of(squares[0] ^ 7); // Horizontal flip: SQ_H1 -> SQ_A1 + + d = item(entry->pawnTable , stm, tbFile).precomp; + } else + d = item(entry->pieceTable, stm, tbFile).precomp; + + // DTZ tables are one-sided, i.e. they store positions only for white to + // move or only for black to move, so check for side to move to be stm, + // early exit otherwise. + if (!IsWDL && !check_dtz_stm(entry, stm, tbFile)) + return *result = CHANGE_STM, T(); + + // Now we are ready to get all the position pieces (but the lead pawns) and + // directly map them to the correct color and square. + b = pos.pieces() ^ leadPawns; + do { + Square s = pop_lsb(&b); + squares[size] = s ^ flipSquares; + pieces[size++] = Piece(pos.piece_on(s) ^ flipColor); + } while (b); + + assert(size >= 2); + + // Then we reorder the pieces to have the same sequence as the one stored + // in precomp->pieces[i]: the sequence that ensures the best compression. + for (int i = leadPawnsCnt; i < size; ++i) + for (int j = i; j < size; ++j) + if (d->pieces[i] == pieces[j]) + { + std::swap(pieces[i], pieces[j]); + std::swap(squares[i], squares[j]); + break; + } + + // Now we map again the squares so that the square of the lead piece is in + // the triangle A1-D1-D4. + if (file_of(squares[0]) > FILE_D) + for (int i = 0; i < size; ++i) + squares[i] ^= 7; // Horizontal flip: SQ_H1 -> SQ_A1 + + // Encode leading pawns starting with the one with minimum MapPawns[] and + // proceeding in ascending order. + if (entry->hasPawns) { + idx = LeadPawnIdx[leadPawnsCnt][squares[0]]; + + std::sort(squares + 1, squares + leadPawnsCnt, pawns_comp); + + for (int i = 1; i < leadPawnsCnt; ++i) + idx += Binomial[i][MapPawns[squares[i]]]; + + goto encode_remaining; // With pawns we have finished special treatments + } + + // In positions withouth pawns, we further flip the squares to ensure leading + // piece is below RANK_5. + if (rank_of(squares[0]) > RANK_4) + for (int i = 0; i < size; ++i) + squares[i] ^= 070; // Vertical flip: SQ_A8 -> SQ_A1 + + // Look for the first piece of the leading group not on the A1-D4 diagonal + // and ensure it is mapped below the diagonal. + for (int i = 0; i < d->groupLen[0]; ++i) { + if (!off_A1H8(squares[i])) + continue; + + if (off_A1H8(squares[i]) > 0) // A1-H8 diagonal flip: SQ_A3 -> SQ_C3 + for (int j = i; j < size; ++j) + squares[j] = Square(((squares[j] >> 3) | (squares[j] << 3)) & 63); + break; + } + + // Encode the leading group. + // + // Suppose we have KRvK. Let's say the pieces are on square numbers wK, wR + // and bK (each 0...63). The simplest way to map this position to an index + // is like this: + // + // index = wK * 64 * 64 + wR * 64 + bK; + // + // But this way the TB is going to have 64*64*64 = 262144 positions, with + // lots of positions being equivalent (because they are mirrors of each + // other) and lots of positions being invalid (two pieces on one square, + // adjacent kings, etc.). + // Usually the first step is to take the wK and bK together. There are just + // 462 ways legal and not-mirrored ways to place the wK and bK on the board. + // Once we have placed the wK and bK, there are 62 squares left for the wR + // Mapping its square from 0..63 to available squares 0..61 can be done like: + // + // wR -= (wR > wK) + (wR > bK); + // + // In words: if wR "comes later" than wK, we deduct 1, and the same if wR + // "comes later" than bK. In case of two same pieces like KRRvK we want to + // place the two Rs "together". If we have 62 squares left, we can place two + // Rs "together" in 62 * 61 / 2 ways (we divide by 2 because rooks can be + // swapped and still get the same position.) + // + // In case we have at least 3 unique pieces (inlcuded kings) we encode them + // together. + if (entry->hasUniquePieces) { + + int adjust1 = squares[1] > squares[0]; + int adjust2 = (squares[2] > squares[0]) + (squares[2] > squares[1]); + + // First piece is below a1-h8 diagonal. MapA1D1D4[] maps the b1-d1-d3 + // triangle to 0...5. There are 63 squares for second piece and and 62 + // (mapped to 0...61) for the third. + if (off_A1H8(squares[0])) + idx = ( MapA1D1D4[squares[0]] * 63 + + (squares[1] - adjust1)) * 62 + + squares[2] - adjust2; + + // First piece is on a1-h8 diagonal, second below: map this occurence to + // 6 to differentiate from the above case, rank_of() maps a1-d4 diagonal + // to 0...3 and finally MapB1H1H7[] maps the b1-h1-h7 triangle to 0..27. + else if (off_A1H8(squares[1])) + idx = ( 6 * 63 + rank_of(squares[0]) * 28 + + MapB1H1H7[squares[1]]) * 62 + + squares[2] - adjust2; + + // First two pieces are on a1-h8 diagonal, third below + else if (off_A1H8(squares[2])) + idx = 6 * 63 * 62 + 4 * 28 * 62 + + rank_of(squares[0]) * 7 * 28 + + (rank_of(squares[1]) - adjust1) * 28 + + MapB1H1H7[squares[2]]; + + // All 3 pieces on the diagonal a1-h8 + else + idx = 6 * 63 * 62 + 4 * 28 * 62 + 4 * 7 * 28 + + rank_of(squares[0]) * 7 * 6 + + (rank_of(squares[1]) - adjust1) * 6 + + (rank_of(squares[2]) - adjust2); + } else + // We don't have at least 3 unique pieces, like in KRRvKBB, just map + // the kings. + idx = MapKK[MapA1D1D4[squares[0]]][squares[1]]; + +encode_remaining: + idx *= d->groupIdx[0]; + Square* groupSq = squares + d->groupLen[0]; + + // Encode remainig pawns then pieces according to square, in ascending order + bool remainingPawns = entry->hasPawns && entry->pawnTable.pawnCount[1]; + + while (d->groupLen[++next]) + { + std::sort(groupSq, groupSq + d->groupLen[next]); + uint64_t n = 0; + + // Map down a square if "comes later" than a square in the previous + // groups (similar to what done earlier for leading group pieces). + for (int i = 0; i < d->groupLen[next]; ++i) + { + auto f = [&](Square s) { return groupSq[i] > s; }; + auto adjust = std::count_if(squares, groupSq, f); + n += Binomial[i + 1][groupSq[i] - adjust - 8 * remainingPawns]; + } + + remainingPawns = false; + idx += n * d->groupIdx[next]; + groupSq += d->groupLen[next]; + } + + // Now that we have the index, decompress the pair and get the score + return map_score(entry, tbFile, decompress_pairs(d, idx), wdl); +} + +// Group together pieces that will be encoded together. The general rule is that +// a group contains pieces of same type and color. The exception is the leading +// group that, in case of positions withouth pawns, can be formed by 3 different +// pieces (default) or by the king pair when there is not a unique piece apart +// from the kings. When there are pawns, pawns are always first in pieces[]. +// +// As example KRKN -> KRK + N, KNNK -> KK + NN, KPPKP -> P + PP + K + K +// +// The actual grouping depends on the TB generator and can be inferred from the +// sequence of pieces in piece[] array. +template +void set_groups(T& e, PairsData* d, int order[], File f) { + + int n = 0, firstLen = e.hasPawns ? 0 : e.hasUniquePieces ? 3 : 2; + d->groupLen[n] = 1; + + // Number of pieces per group is stored in groupLen[], for instance in KRKN + // the encoder will default on '111', so groupLen[] will be (3, 1). + for (int i = 1; i < e.pieceCount; ++i) + if (--firstLen > 0 || d->pieces[i] == d->pieces[i - 1]) + d->groupLen[n]++; + else + d->groupLen[++n] = 1; + + d->groupLen[++n] = 0; // Zero-terminated + + // The sequence in pieces[] defines the groups, but not the order in which + // they are encoded. If the pieces in a group g can be combined on the board + // in N(g) different ways, then the position encoding will be of the form: + // + // g1 * N(g2) * N(g3) + g2 * N(g3) + g3 + // + // This ensures unique encoding for the whole position. The order of the + // groups is a per-table parameter and could not follow the canonical leading + // pawns/pieces -> remainig pawns -> remaining pieces. In particular the + // first group is at order[0] position and the remaining pawns, when present, + // are at order[1] position. + bool pp = e.hasPawns && e.pawnTable.pawnCount[1]; // Pawns on both sides + int next = pp ? 2 : 1; + int freeSquares = 64 - d->groupLen[0] - (pp ? d->groupLen[1] : 0); + uint64_t idx = 1; + + for (int k = 0; next < n || k == order[0] || k == order[1]; ++k) + if (k == order[0]) // Leading pawns or pieces + { + d->groupIdx[0] = idx; + idx *= e.hasPawns ? LeadPawnsSize[d->groupLen[0]][f] + : e.hasUniquePieces ? 31332 : 462; + } + else if (k == order[1]) // Remaining pawns + { + d->groupIdx[1] = idx; + idx *= Binomial[d->groupLen[1]][48 - d->groupLen[0]]; + } + else // Remainig pieces + { + d->groupIdx[next] = idx; + idx *= Binomial[d->groupLen[next]][freeSquares]; + freeSquares -= d->groupLen[next++]; + } + + d->groupIdx[n] = idx; +} + +// In Recursive Pairing each symbol represents a pair of childern symbols. So +// read d->btree[] symbols data and expand each one in his left and right child +// symbol until reaching the leafs that represent the symbol value. +uint8_t set_symlen(PairsData* d, Sym s, std::vector& visited) { + + visited[s] = true; // We can set it now because tree is acyclic + Sym sr = d->btree[s].get(); + + if (sr == 0xFFF) + return 0; + + Sym sl = d->btree[s].get(); + + if (!visited[sl]) + d->symlen[sl] = set_symlen(d, sl, visited); + + if (!visited[sr]) + d->symlen[sr] = set_symlen(d, sr, visited); + + return d->symlen[sl] + d->symlen[sr] + 1; +} + +uint8_t* set_sizes(PairsData* d, uint8_t* data) { + + d->flags = *data++; + + if (d->flags & TBFlag::SingleValue) { + d->blocksNum = d->blockLengthSize = 0; + d->span = d->sparseIndexSize = 0; // Broken MSVC zero-init + d->minSymLen = *data++; // Here we store the single value + return data; + } + + // groupLen[] is a zero-terminated list of group lengths, the last groupIdx[] + // element stores the biggest index that is the tb size. + uint64_t tbSize = d->groupIdx[std::find(d->groupLen, d->groupLen + 7, 0) - d->groupLen]; + + d->sizeofBlock = 1ULL << *data++; + d->span = 1ULL << *data++; + d->sparseIndexSize = (tbSize + d->span - 1) / d->span; // Round up + int padding = number(data++); + d->blocksNum = number(data); data += sizeof(uint32_t); + d->blockLengthSize = d->blocksNum + padding; // Padded to ensure SparseIndex[] + // does not point out of range. + d->maxSymLen = *data++; + d->minSymLen = *data++; + d->lowestSym = (Sym*)data; + d->base64.resize(d->maxSymLen - d->minSymLen + 1); + + // The canonical code is ordered such that longer symbols (in terms of + // the number of bits of their Huffman code) have lower numeric value, + // so that d->lowestSym[i] >= d->lowestSym[i+1] (when read as LittleEndian). + // Starting from this we compute a base64[] table indexed by symbol length + // and containing 64 bit values so that d->base64[i] >= d->base64[i+1]. + // See http://www.eecs.harvard.edu/~michaelm/E210/huffman.pdf + for (int i = d->base64.size() - 2; i >= 0; --i) { + d->base64[i] = (d->base64[i + 1] + number(&d->lowestSym[i]) + - number(&d->lowestSym[i + 1])) / 2; + + assert(d->base64[i] * 2 >= d->base64[i+1]); + } + + // Now left-shift by an amount so that d->base64[i] gets shifted 1 bit more + // than d->base64[i+1] and given the above assert condition, we ensure that + // d->base64[i] >= d->base64[i+1]. Moreover for any symbol s64 of length i + // and right-padded to 64 bits holds d->base64[i-1] >= s64 >= d->base64[i]. + for (size_t i = 0; i < d->base64.size(); ++i) + d->base64[i] <<= 64 - i - d->minSymLen; // Right-padding to 64 bits + + data += d->base64.size() * sizeof(Sym); + d->symlen.resize(number(data)); data += sizeof(uint16_t); + d->btree = (LR*)data; + + // The comrpession scheme used is "Recursive Pairing", that replaces the most + // frequent adjacent pair of symbols in the source message by a new symbol, + // reevaluating the frequencies of all of the symbol pairs with respect to + // the extended alphabet, and then repeating the process. + // See http://www.larsson.dogma.net/dcc99.pdf + std::vector visited(d->symlen.size()); + + for (Sym sym = 0; sym < d->symlen.size(); ++sym) + if (!visited[sym]) + d->symlen[sym] = set_symlen(d, sym, visited); + + return data + d->symlen.size() * sizeof(LR) + (d->symlen.size() & 1); +} + +template +uint8_t* set_dtz_map(WDLEntry&, T&, uint8_t*, File) { return nullptr; } + +template +uint8_t* set_dtz_map(DTZEntry&, T& p, uint8_t* data, File maxFile) { + + p.map = data; + + for (File f = FILE_A; f <= maxFile; ++f) { + if (item(p, 0, f).precomp->flags & TBFlag::Mapped) + for (int i = 0; i < 4; ++i) { // Sequence like 3,x,x,x,1,x,0,2,x,x + item(p, 0, f).map_idx[i] = (uint16_t)(data - p.map + 1); + data += *data + 1; + } + } + + return data += (uintptr_t)data & 1; // Word alignment +} + +template +void do_init(Entry& e, T& p, uint8_t* data) { + + const bool IsWDL = std::is_same::value; + + PairsData* d; + + enum { Split = 1, HasPawns = 2 }; + + assert(e.hasPawns == !!(*data & HasPawns)); + assert((e.key != e.key2) == !!(*data & Split)); + + data++; // First byte stores flags + + const int Sides = IsWDL && (e.key != e.key2) ? 2 : 1; + const File MaxFile = e.hasPawns ? FILE_D : FILE_A; + + bool pp = e.hasPawns && e.pawnTable.pawnCount[1]; // Pawns on both sides + + assert(!pp || e.pawnTable.pawnCount[0]); + + for (File f = FILE_A; f <= MaxFile; ++f) { + + for (int i = 0; i < Sides; i++) + item(p, i, f).precomp = new PairsData(); + + int order[][2] = { { *data & 0xF, pp ? *(data + 1) & 0xF : 0xF }, + { *data >> 4, pp ? *(data + 1) >> 4 : 0xF } }; + data += 1 + pp; + + for (int k = 0; k < e.pieceCount; ++k, ++data) + for (int i = 0; i < Sides; i++) + item(p, i, f).precomp->pieces[k] = Piece(i ? *data >> 4 : *data & 0xF); + + for (int i = 0; i < Sides; ++i) + set_groups(e, item(p, i, f).precomp, order[i], f); + } + + data += (uintptr_t)data & 1; // Word alignment + + for (File f = FILE_A; f <= MaxFile; ++f) + for (int i = 0; i < Sides; i++) + data = set_sizes(item(p, i, f).precomp, data); + + if (!IsWDL) + data = set_dtz_map(e, p, data, MaxFile); + + for (File f = FILE_A; f <= MaxFile; ++f) + for (int i = 0; i < Sides; i++) { + (d = item(p, i, f).precomp)->sparseIndex = (SparseEntry*)data; + data += d->sparseIndexSize * sizeof(SparseEntry); + } + + for (File f = FILE_A; f <= MaxFile; ++f) + for (int i = 0; i < Sides; i++) { + (d = item(p, i, f).precomp)->blockLength = (uint16_t*)data; + data += d->blockLengthSize * sizeof(uint16_t); + } + + for (File f = FILE_A; f <= MaxFile; ++f) + for (int i = 0; i < Sides; i++) { + data = (uint8_t*)(((uintptr_t)data + 0x3F) & ~0x3F); // 64 byte alignment + (d = item(p, i, f).precomp)->data = data; + data += d->blocksNum * d->sizeofBlock; + } +} + +template +void* init(Entry& e, const Position& pos) { + + const bool IsWDL = std::is_same::value; + + static Mutex mutex; + + // Avoid a thread reads 'ready' == true while another is still in do_init(), + // this could happen due to compiler reordering. + if (e.ready.load(std::memory_order_acquire)) + return e.baseAddress; + + std::unique_lock lk(mutex); + + if (e.ready.load(std::memory_order_relaxed)) // Recheck under lock + return e.baseAddress; + + // Pieces strings in decreasing order for each color, like ("KPP","KR") + std::string fname, w, b; + for (PieceType pt = KING; pt >= PAWN; --pt) { + w += std::string(popcount(pos.pieces(WHITE, pt)), PieceToChar[pt]); + b += std::string(popcount(pos.pieces(BLACK, pt)), PieceToChar[pt]); + } + + const uint8_t TB_MAGIC[][4] = { { 0xD7, 0x66, 0x0C, 0xA5 }, + { 0x71, 0xE8, 0x23, 0x5D } }; + + fname = (e.key == pos.material_key() ? w + 'v' + b : b + 'v' + w) + + (IsWDL ? ".rtbw" : ".rtbz"); + + uint8_t* data = TBFile(fname).map(&e.baseAddress, &e.mapping, TB_MAGIC[IsWDL]); + if (data) + e.hasPawns ? do_init(e, e.pawnTable, data) : do_init(e, e.pieceTable, data); + + e.ready.store(true, std::memory_order_release); + return e.baseAddress; +} + +template::type> +T probe_table(const Position& pos, ProbeState* result, WDLScore wdl = WDLDraw) { + + if (!(pos.pieces() ^ pos.pieces(KING))) + return T(WDLDraw); // KvK + + E* entry = EntryTable.get(pos.material_key()); + + if (!entry || !init(*entry, pos)) + return *result = FAIL, T(); + + return do_probe_table(pos, entry, wdl, result); +} + +// For a position where the side to move has a winning capture it is not necessary +// to store a winning value so the generator treats such positions as "don't cares" +// and tries to assign to it a value that improves the compression ratio. Similarly, +// if the side to move has a drawing capture, then the position is at least drawn. +// If the position is won, then the TB needs to store a win value. But if the +// position is drawn, the TB may store a loss value if that is better for compression. +// All of this means that during probing, the engine must look at captures and probe +// their results and must probe the position itself. The "best" result of these +// probes is the correct result for the position. +// DTZ table don't store values when a following move is a zeroing winning move +// (winning capture or winning pawn move). Also DTZ store wrong values for positions +// where the best move is an ep-move (even if losing). So in all these cases set +// the state to ZEROING_BEST_MOVE. +template +WDLScore search(Position& pos, ProbeState* result) { + + WDLScore value, bestValue = WDLLoss; + StateInfo st; + + auto moveList = MoveList(pos); + size_t totalCount = moveList.size(), moveCount = 0; + + for (const Move& move : moveList) + { + if ( !pos.capture(move) + && (!CheckZeroingMoves || type_of(pos.moved_piece(move)) != PAWN)) + continue; + + moveCount++; + + pos.do_move(move, st); + value = -search(pos, result); + pos.undo_move(move); + + if (*result == FAIL) + return WDLDraw; + + if (value > bestValue) + { + bestValue = value; + + if (value >= WDLWin) + { + *result = ZEROING_BEST_MOVE; // Winning DTZ-zeroing move + return value; + } + } + } + + // In case we have already searched all the legal moves we don't have to probe + // the TB because the stored score could be wrong. For instance TB tables + // do not contain information on position with ep rights, so in this case + // the result of probe_wdl_table is wrong. Also in case of only capture + // moves, for instance here 4K3/4q3/6p1/2k5/6p1/8/8/8 w - - 0 7, we have to + // return with ZEROING_BEST_MOVE set. + bool noMoreMoves = (moveCount && moveCount == totalCount); + + if (noMoreMoves) + value = bestValue; + else + { + value = probe_table(pos, result); + + if (*result == FAIL) + return WDLDraw; + } + + // DTZ stores a "don't care" value if bestValue is a win + if (bestValue >= value) + return *result = ( bestValue > WDLDraw + || noMoreMoves ? ZEROING_BEST_MOVE : OK), bestValue; + + return *result = OK, value; +} + +} // namespace + +void Tablebases::init(const std::string& paths) { + + EntryTable.clear(); + MaxCardinality = 0; + TBFile::Paths = paths; + + if (paths.empty() || paths == "") + return; + + // MapB1H1H7[] encodes a square below a1-h8 diagonal to 0..27 + int code = 0; + for (Square s = SQ_A1; s <= SQ_H8; ++s) + if (off_A1H8(s) < 0) + MapB1H1H7[s] = code++; + + // MapA1D1D4[] encodes a square in the a1-d1-d4 triangle to 0..9 + std::vector diagonal; + code = 0; + for (Square s = SQ_A1; s <= SQ_D4; ++s) + if (off_A1H8(s) < 0 && file_of(s) <= FILE_D) + MapA1D1D4[s] = code++; + + else if (!off_A1H8(s) && file_of(s) <= FILE_D) + diagonal.push_back(s); + + // Diagonal squares are encoded as last ones + for (auto s : diagonal) + MapA1D1D4[s] = code++; + + // MapKK[] encodes all the 461 possible legal positions of two kings where + // the first is in the a1-d1-d4 triangle. If the first king is on the a1-d4 + // diagonal, the other one shall not to be above the a1-h8 diagonal. + std::vector> bothOnDiagonal; + code = 0; + for (int idx = 0; idx < 10; idx++) + for (Square s1 = SQ_A1; s1 <= SQ_D4; ++s1) + if (MapA1D1D4[s1] == idx && (idx || s1 == SQ_B1)) // SQ_B1 is mapped to 0 + { + for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2) + if ((PseudoAttacks[KING][s1] | s1) & s2) + continue; // Illegal position + + else if (!off_A1H8(s1) && off_A1H8(s2) > 0) + continue; // First on diagonal, second above + + else if (!off_A1H8(s1) && !off_A1H8(s2)) + bothOnDiagonal.push_back(std::make_pair(idx, s2)); + + else + MapKK[idx][s2] = code++; + } + + // Legal positions with both kings on diagonal are encoded as last ones + for (auto p : bothOnDiagonal) + MapKK[p.first][p.second] = code++; + + // Binomial[] stores the Binomial Coefficents using Pascal rule. There + // are Binomial[k][n] ways to choose k elements from a set of n elements. + Binomial[0][0] = 1; + + for (int n = 1; n < 64; n++) // Squares + for (int k = 0; k < 6 && k <= n; ++k) // Pieces + Binomial[k][n] = (k > 0 ? Binomial[k - 1][n - 1] : 0) + + (k < n ? Binomial[k ][n - 1] : 0); + + // MapPawns[s] encodes squares a2-h7 to 0..47. This is the number of possible + // available squares when the leading one is in 's'. Moreover the pawn with + // highest MapPawns[] is the leading pawn, the one nearest the edge and, + // among pawns with same file, the one with lowest rank. + int availableSquares = 47; // Available squares when lead pawn is in a2 + + // Init the tables for the encoding of leading pawns group: with 6-men TB we + // can have up to 4 leading pawns (KPPPPK). + for (int leadPawnsCnt = 1; leadPawnsCnt <= 4; ++leadPawnsCnt) + for (File f = FILE_A; f <= FILE_D; ++f) + { + // Restart the index at every file because TB table is splitted + // by file, so we can reuse the same index for different files. + int idx = 0; + + // Sum all possible combinations for a given file, starting with + // the leading pawn on rank 2 and increasing the rank. + for (Rank r = RANK_2; r <= RANK_7; ++r) + { + Square sq = make_square(f, r); + + // Compute MapPawns[] at first pass. + // If sq is the leading pawn square, any other pawn cannot be + // below or more toward the edge of sq. There are 47 available + // squares when sq = a2 and reduced by 2 for any rank increase + // due to mirroring: sq == a3 -> no a2, h2, so MapPawns[a3] = 45 + if (leadPawnsCnt == 1) + { + MapPawns[sq] = availableSquares--; + MapPawns[sq ^ 7] = availableSquares--; // Horizontal flip + } + LeadPawnIdx[leadPawnsCnt][sq] = idx; + idx += Binomial[leadPawnsCnt - 1][MapPawns[sq]]; + } + // After a file is traversed, store the cumulated per-file index + LeadPawnsSize[leadPawnsCnt][f] = idx; + } + + for (PieceType p1 = PAWN; p1 < KING; ++p1) { + EntryTable.insert({KING, p1, KING}); + + for (PieceType p2 = PAWN; p2 <= p1; ++p2) { + EntryTable.insert({KING, p1, p2, KING}); + EntryTable.insert({KING, p1, KING, p2}); + + for (PieceType p3 = PAWN; p3 < KING; ++p3) + EntryTable.insert({KING, p1, p2, KING, p3}); + + for (PieceType p3 = PAWN; p3 <= p2; ++p3) { + EntryTable.insert({KING, p1, p2, p3, KING}); + + for (PieceType p4 = PAWN; p4 <= p3; ++p4) + EntryTable.insert({KING, p1, p2, p3, p4, KING}); + + for (PieceType p4 = PAWN; p4 < KING; ++p4) + EntryTable.insert({KING, p1, p2, p3, KING, p4}); + } + + for (PieceType p3 = PAWN; p3 <= p1; ++p3) + for (PieceType p4 = PAWN; p4 <= (p1 == p3 ? p2 : p3); ++p4) + EntryTable.insert({KING, p1, p2, KING, p3, p4}); + } + } + + sync_cout << "info string Found " << EntryTable.size() << " tablebases" << sync_endl; +} + +// Probe the WDL table for a particular position. +// If *result != FAIL, the probe was successful. +// The return value is from the point of view of the side to move: +// -2 : loss +// -1 : loss, but draw under 50-move rule +// 0 : draw +// 1 : win, but draw under 50-move rule +// 2 : win +WDLScore Tablebases::probe_wdl(Position& pos, ProbeState* result) { + + *result = OK; + return search(pos, result); +} + +// Probe the DTZ table for a particular position. +// If *result != FAIL, the probe was successful. +// The return value is from the point of view of the side to move: +// n < -100 : loss, but draw under 50-move rule +// -100 <= n < -1 : loss in n ply (assuming 50-move counter == 0) +// 0 : draw +// 1 < n <= 100 : win in n ply (assuming 50-move counter == 0) +// 100 < n : win, but draw under 50-move rule +// +// The return value n can be off by 1: a return value -n can mean a loss +// in n+1 ply and a return value +n can mean a win in n+1 ply. This +// cannot happen for tables with positions exactly on the "edge" of +// the 50-move rule. +// +// This implies that if dtz > 0 is returned, the position is certainly +// a win if dtz + 50-move-counter <= 99. Care must be taken that the engine +// picks moves that preserve dtz + 50-move-counter <= 99. +// +// If n = 100 immediately after a capture or pawn move, then the position +// is also certainly a win, and during the whole phase until the next +// capture or pawn move, the inequality to be preserved is +// dtz + 50-movecounter <= 100. +// +// In short, if a move is available resulting in dtz + 50-move-counter <= 99, +// then do not accept moves leading to dtz + 50-move-counter == 100. +int Tablebases::probe_dtz(Position& pos, ProbeState* result) { + + *result = OK; + WDLScore wdl = search(pos, result); + + if (*result == FAIL || wdl == WDLDraw) // DTZ tables don't store draws + return 0; + + // DTZ stores a 'don't care' value in this case, or even a plain wrong + // one as in case the best move is a losing ep, so it cannot be probed. + if (*result == ZEROING_BEST_MOVE) + return dtz_before_zeroing(wdl); + + int dtz = probe_table(pos, result, wdl); + + if (*result == FAIL) + return 0; + + if (*result != CHANGE_STM) + return (dtz + 100 * (wdl == WDLBlessedLoss || wdl == WDLCursedWin)) * sign_of(wdl); + + // DTZ stores results for the other side, so we need to do a 1-ply search and + // find the winning move that minimizes DTZ. + StateInfo st; + int minDTZ = 0xFFFF; + + for (const Move& move : MoveList(pos)) + { + bool zeroing = pos.capture(move) || type_of(pos.moved_piece(move)) == PAWN; + + pos.do_move(move, st); + + // For zeroing moves we want the dtz of the move _before_ doing it, + // otherwise we will get the dtz of the next move sequence. Search the + // position after the move to get the score sign (because even in a + // winning position we could make a losing capture or going for a draw). + dtz = zeroing ? -dtz_before_zeroing(search(pos, result)) + : -probe_dtz(pos, result); + + pos.undo_move(move); + + if (*result == FAIL) + return 0; + + // Convert result from 1-ply search. Zeroing moves are already accounted + // by dtz_before_zeroing() that returns the DTZ of the previous move. + if (!zeroing) + dtz += sign_of(dtz); + + // Skip the draws and if we are winning only pick positive dtz + if (dtz < minDTZ && sign_of(dtz) == sign_of(wdl)) + minDTZ = dtz; + } + + // Special handle a mate position, when there are no legal moves, in this + // case return value is somewhat arbitrary, so stick to the original TB code + // that returns -1 in this case. + return minDTZ == 0xFFFF ? -1 : minDTZ; +} + +// Check whether there has been at least one repetition of positions +// since the last capture or pawn move. +static int has_repeated(StateInfo *st) +{ + while (1) { + int i = 4, e = std::min(st->rule50, st->pliesFromNull); + + if (e < i) + return 0; + + StateInfo *stp = st->previous->previous; + + do { + stp = stp->previous->previous; + + if (stp->key == st->key) + return 1; + + i += 2; + } while (i <= e); + + st = st->previous; + } +} + +// Use the DTZ tables to filter out moves that don't preserve the win or draw. +// If the position is lost, but DTZ is fairly high, only keep moves that +// maximise DTZ. +// +// A return value false indicates that not all probes were successful and that +// no moves were filtered out. +bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves, Value& score) +{ + assert(rootMoves.size()); + + ProbeState result; + int dtz = probe_dtz(pos, &result); + + if (result == FAIL) + return false; + + StateInfo st; + + // Probe each move + for (size_t i = 0; i < rootMoves.size(); ++i) { + Move move = rootMoves[i].pv[0]; + pos.do_move(move, st); + int v = 0; + + if (pos.checkers() && dtz > 0) { + ExtMove s[MAX_MOVES]; + + if (generate(pos, s) == s) + v = 1; + } + + if (!v) { + if (st.rule50 != 0) { + v = -probe_dtz(pos, &result); + + if (v > 0) + ++v; + else if (v < 0) + --v; + } else { + v = -probe_wdl(pos, &result); + v = dtz_before_zeroing(WDLScore(v)); + } + } + + pos.undo_move(move); + + if (result == FAIL) + return false; + + rootMoves[i].score = (Value)v; + } + + // Obtain 50-move counter for the root position. + // In Stockfish there seems to be no clean way, so we do it like this: + int cnt50 = st.previous ? st.previous->rule50 : 0; + + // Use 50-move counter to determine whether the root position is + // won, lost or drawn. + WDLScore wdl = WDLDraw; + + if (dtz > 0) + wdl = (dtz + cnt50 <= 100) ? WDLWin : WDLCursedWin; + else if (dtz < 0) + wdl = (-dtz + cnt50 <= 100) ? WDLLoss : WDLBlessedLoss; + + // Determine the score to report to the user. + score = WDL_to_value[wdl + 2]; + + // If the position is winning or losing, but too few moves left, adjust the + // score to show how close it is to winning or losing. + // NOTE: int(PawnValueEg) is used as scaling factor in score_to_uci(). + if (wdl == WDLCursedWin && dtz <= 100) + score = (Value)(((200 - dtz - cnt50) * int(PawnValueEg)) / 200); + else if (wdl == WDLBlessedLoss && dtz >= -100) + score = -(Value)(((200 + dtz - cnt50) * int(PawnValueEg)) / 200); + + // Now be a bit smart about filtering out moves. + size_t j = 0; + + if (dtz > 0) { // winning (or 50-move rule draw) + int best = 0xffff; + + for (size_t i = 0; i < rootMoves.size(); ++i) { + int v = rootMoves[i].score; + + if (v > 0 && v < best) + best = v; + } + + int max = best; + + // If the current phase has not seen repetitions, then try all moves + // that stay safely within the 50-move budget, if there are any. + if (!has_repeated(st.previous) && best + cnt50 <= 99) + max = 99 - cnt50; + + for (size_t i = 0; i < rootMoves.size(); ++i) { + int v = rootMoves[i].score; + + if (v > 0 && v <= max) + rootMoves[j++] = rootMoves[i]; + } + } else if (dtz < 0) { // losing (or 50-move rule draw) + int best = 0; + + for (size_t i = 0; i < rootMoves.size(); ++i) { + int v = rootMoves[i].score; + + if (v < best) + best = v; + } + + // Try all moves, unless we approach or have a 50-move rule draw. + if (-best * 2 + cnt50 < 100) + return true; + + for (size_t i = 0; i < rootMoves.size(); ++i) { + if (rootMoves[i].score == best) + rootMoves[j++] = rootMoves[i]; + } + } else { // drawing + // Try all moves that preserve the draw. + for (size_t i = 0; i < rootMoves.size(); ++i) { + if (rootMoves[i].score == 0) + rootMoves[j++] = rootMoves[i]; + } + } + + rootMoves.resize(j, Search::RootMove(MOVE_NONE)); + + return true; +} + +// Use the WDL tables to filter out moves that don't preserve the win or draw. +// This is a fallback for the case that some or all DTZ tables are missing. +// +// A return value false indicates that not all probes were successful and that +// no moves were filtered out. +bool Tablebases::root_probe_wdl(Position& pos, Search::RootMoves& rootMoves, Value& score) +{ + ProbeState result; + + WDLScore wdl = Tablebases::probe_wdl(pos, &result); + + if (result == FAIL) + return false; + + score = WDL_to_value[wdl + 2]; + + StateInfo st; + + int best = WDLLoss; + + // Probe each move + for (size_t i = 0; i < rootMoves.size(); ++i) { + Move move = rootMoves[i].pv[0]; + pos.do_move(move, st); + WDLScore v = -Tablebases::probe_wdl(pos, &result); + pos.undo_move(move); + + if (result == FAIL) + return false; + + rootMoves[i].score = (Value)v; + + if (v > best) + best = v; + } + + size_t j = 0; + + for (size_t i = 0; i < rootMoves.size(); ++i) { + if (rootMoves[i].score == best) + rootMoves[j++] = rootMoves[i]; + } + + rootMoves.resize(j, Search::RootMove(MOVE_NONE)); + + return true; +} diff --git a/src/syzygy/tbprobe.h b/src/syzygy/tbprobe.h new file mode 100644 index 0000000..287b617 --- /dev/null +++ b/src/syzygy/tbprobe.h @@ -0,0 +1,79 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (c) 2013 Ronald de Man + Copyright (C) 2016-2018 Marco Costalba, Lucas Braesch + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef TBPROBE_H +#define TBPROBE_H + +#include + +#include "../search.h" + +namespace Tablebases { + +enum WDLScore { + WDLLoss = -2, // Loss + WDLBlessedLoss = -1, // Loss, but draw under 50-move rule + WDLDraw = 0, // Draw + WDLCursedWin = 1, // Win, but draw under 50-move rule + WDLWin = 2, // Win + + WDLScoreNone = -1000 +}; + +// Possible states after a probing operation +enum ProbeState { + FAIL = 0, // Probe failed (missing file table) + OK = 1, // Probe succesful + CHANGE_STM = -1, // DTZ should check the other side + ZEROING_BEST_MOVE = 2 // Best move zeroes DTZ (capture or pawn move) +}; + +extern int MaxCardinality; + +void init(const std::string& paths); +WDLScore probe_wdl(Position& pos, ProbeState* result); +int probe_dtz(Position& pos, ProbeState* result); +bool root_probe(Position& pos, Search::RootMoves& rootMoves, Value& score); +bool root_probe_wdl(Position& pos, Search::RootMoves& rootMoves, Value& score); +void filter_root_moves(Position& pos, Search::RootMoves& rootMoves); + +inline std::ostream& operator<<(std::ostream& os, const WDLScore v) { + + os << (v == WDLLoss ? "Loss" : + v == WDLBlessedLoss ? "Blessed loss" : + v == WDLDraw ? "Draw" : + v == WDLCursedWin ? "Cursed win" : + v == WDLWin ? "Win" : "None"); + + return os; +} + +inline std::ostream& operator<<(std::ostream& os, const ProbeState v) { + + os << (v == FAIL ? "Failed" : + v == OK ? "Success" : + v == CHANGE_STM ? "Probed opponent side" : + v == ZEROING_BEST_MOVE ? "Best move zeroes DTZ" : "None"); + + return os; +} + +} + +#endif diff --git a/src/thread.cpp b/src/thread.cpp new file mode 100644 index 0000000..97beb58 --- /dev/null +++ b/src/thread.cpp @@ -0,0 +1,199 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include // For std::count +#include + +#include "movegen.h" +#include "search.h" +#include "thread.h" +#include "uci.h" +#include "syzygy/tbprobe.h" + +ThreadPool Threads; // Global object + + +/// Thread constructor launches the thread and waits until it goes to sleep +/// in idle_loop(). Note that 'searching' and 'exit' should be alredy set. + +Thread::Thread(size_t n) : idx(n), stdThread(&Thread::idle_loop, this) { + + wait_for_search_finished(); +} + + +/// Thread destructor wakes up the thread in idle_loop() and waits +/// for its termination. Thread should be already waiting. + +Thread::~Thread() { + + assert(!searching); + + exit = true; + start_searching(); + stdThread.join(); +} + + +/// Thread::clear() reset histories, usually before a new game + +void Thread::clear() { + + counterMoves.fill(MOVE_NONE); + mainHistory.fill(0); + captureHistory.fill(0); + + for (auto& to : contHistory) + for (auto& h : to) + h.fill(0); + + contHistory[NO_PIECE][0].fill(Search::CounterMovePruneThreshold - 1); +} + +/// Thread::start_searching() wakes up the thread that will start the search + +void Thread::start_searching() { + + std::lock_guard lk(mutex); + searching = true; + cv.notify_one(); // Wake up the thread in idle_loop() +} + + +/// Thread::wait_for_search_finished() blocks on the condition variable +/// until the thread has finished searching. + +void Thread::wait_for_search_finished() { + + std::unique_lock lk(mutex); + cv.wait(lk, [&]{ return !searching; }); +} + + +/// Thread::idle_loop() is where the thread is parked, blocked on the +/// condition variable, when it has no work to do. + +void Thread::idle_loop() { + + // If OS already scheduled us on a different group than 0 then don't overwrite + // the choice, eventually we are one of many one-threaded processes running on + // some Windows NUMA hardware, for instance in fishtest. To make it simple, + // just check if running threads are below a threshold, in this case all this + // NUMA machinery is not needed. + if (Options["Threads"] >= 8) + WinProcGroup::bindThisThread(idx); + + while (true) + { + std::unique_lock lk(mutex); + searching = false; + cv.notify_one(); // Wake up anyone waiting for search finished + cv.wait(lk, [&]{ return searching; }); + + if (exit) + return; + + lk.unlock(); + + search(); + } +} + +/// ThreadPool::set() creates/destroys threads to match the requested number. +/// Created and launced threads wil go immediately to sleep in idle_loop. +/// Upon resizing, threads are recreated to allow for binding if necessary. + +void ThreadPool::set(size_t requested) { + + if (size() > 0) { // destroy any existing thread(s) + main()->wait_for_search_finished(); + + while (size() > 0) + delete back(), pop_back(); + } + + if (requested > 0) { // create new thread(s) + push_back(new MainThread(0)); + + while (size() < requested) + push_back(new Thread(size())); + clear(); + } +} + +/// ThreadPool::clear() sets threadPool data to initial values. + +void ThreadPool::clear() { + + for (Thread* th : *this) + th->clear(); + + main()->callsCnt = 0; + main()->previousScore = VALUE_INFINITE; + main()->previousTimeReduction = 1; +} + +/// ThreadPool::start_thinking() wakes up main thread waiting in idle_loop() and +/// returns immediately. Main thread will wake up other threads and start the search. + +void ThreadPool::start_thinking(Position& pos, StateListPtr& states, + const Search::LimitsType& limits, bool ponderMode) { + + main()->wait_for_search_finished(); + + stopOnPonderhit = stop = false; + ponder = ponderMode; + Search::Limits = limits; + Search::RootMoves rootMoves; + + for (const auto& m : MoveList(pos)) + if ( limits.searchmoves.empty() + || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m)) + rootMoves.emplace_back(m); + + if (!rootMoves.empty()) + Tablebases::filter_root_moves(pos, rootMoves); + + // After ownership transfer 'states' becomes empty, so if we stop the search + // and call 'go' again without setting a new position states.get() == NULL. + assert(states.get() || setupStates.get()); + + if (states.get()) + setupStates = std::move(states); // Ownership transfer, states is now empty + + // We use Position::set() to set root position across threads. But there are + // some StateInfo fields (previous, pliesFromNull, capturedPiece) that cannot + // be deduced from a fen string, so set() clears them and to not lose the info + // we need to backup and later restore setupStates->back(). Note that setupStates + // is shared by threads but is accessed in read-only mode. + StateInfo tmp = setupStates->back(); + + for (Thread* th : *this) + { + th->nodes = th->tbHits = th->nmp_ply = th->nmp_odd = 0; + th->rootDepth = th->completedDepth = DEPTH_ZERO; + th->rootMoves = rootMoves; + th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th); + } + + setupStates->back() = tmp; + + main()->start_searching(); +} diff --git a/src/thread.h b/src/thread.h new file mode 100644 index 0000000..1397449 --- /dev/null +++ b/src/thread.h @@ -0,0 +1,123 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef THREAD_H_INCLUDED +#define THREAD_H_INCLUDED + +#include +#include +#include +#include +#include + +#include "material.h" +#include "movepick.h" +#include "pawns.h" +#include "position.h" +#include "search.h" +#include "thread_win32.h" + + +/// Thread class keeps together all the thread-related stuff. We use +/// per-thread pawn and material hash tables so that once we get a +/// pointer to an entry its life time is unlimited and we don't have +/// to care about someone changing the entry under our feet. + +class Thread { + + Mutex mutex; + ConditionVariable cv; + size_t idx; + bool exit = false, searching = true; // Set before starting std::thread + std::thread stdThread; + +public: + explicit Thread(size_t); + virtual ~Thread(); + virtual void search(); + void clear(); + void idle_loop(); + void start_searching(); + void wait_for_search_finished(); + + Pawns::Table pawnsTable; + Material::Table materialTable; + Endgames endgames; + size_t PVIdx; + int selDepth, nmp_ply, nmp_odd; + std::atomic nodes, tbHits; + + Position rootPos; + Search::RootMoves rootMoves; + Depth rootDepth, completedDepth; + CounterMoveHistory counterMoves; + ButterflyHistory mainHistory; + CapturePieceToHistory captureHistory; + ContinuationHistory contHistory; +}; + + +/// MainThread is a derived class specific for main thread + +struct MainThread : public Thread { + + using Thread::Thread; + + void search() override; + void check_time(); + + bool failedLow; + double bestMoveChanges, previousTimeReduction; + Value previousScore; + int callsCnt; +}; + + +/// ThreadPool struct handles all the threads-related stuff like init, starting, +/// parking and, most importantly, launching a thread. All the access to threads +/// is done through this class. + +struct ThreadPool : public std::vector { + + void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false); + void clear(); + void set(size_t); + + MainThread* main() const { return static_cast(front()); } + uint64_t nodes_searched() const { return accumulate(&Thread::nodes); } + uint64_t tb_hits() const { return accumulate(&Thread::tbHits); } + + std::atomic_bool stop, ponder, stopOnPonderhit; + +private: + StateListPtr setupStates; + + uint64_t accumulate(std::atomic Thread::* member) const { + + uint64_t sum = 0; + for (Thread* th : *this) + sum += (th->*member).load(std::memory_order_relaxed); + return sum; + } +}; + +extern ThreadPool Threads; + +#endif // #ifndef THREAD_H_INCLUDED diff --git a/src/thread_win32.h b/src/thread_win32.h new file mode 100644 index 0000000..5da186a --- /dev/null +++ b/src/thread_win32.h @@ -0,0 +1,70 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef THREAD_WIN32_H_INCLUDED +#define THREAD_WIN32_H_INCLUDED + +/// STL thread library used by mingw and gcc when cross compiling for Windows +/// relies on libwinpthread. Currently libwinpthread implements mutexes directly +/// on top of Windows semaphores. Semaphores, being kernel objects, require kernel +/// mode transition in order to lock or unlock, which is very slow compared to +/// interlocked operations (about 30% slower on bench test). To work around this +/// issue, we define our wrappers to the low level Win32 calls. We use critical +/// sections to support Windows XP and older versions. Unfortunately, cond_wait() +/// is racy between unlock() and WaitForSingleObject() but they have the same +/// speed performance as the SRW locks. + +#include +#include + +#if defined(_WIN32) && !defined(_MSC_VER) + +#ifndef NOMINMAX +# define NOMINMAX // Disable macros min() and max() +#endif + +#define WIN32_LEAN_AND_MEAN +#include +#undef WIN32_LEAN_AND_MEAN +#undef NOMINMAX + +/// Mutex and ConditionVariable struct are wrappers of the low level locking +/// machinery and are modeled after the corresponding C++11 classes. + +struct Mutex { + Mutex() { InitializeCriticalSection(&cs); } + ~Mutex() { DeleteCriticalSection(&cs); } + void lock() { EnterCriticalSection(&cs); } + void unlock() { LeaveCriticalSection(&cs); } + +private: + CRITICAL_SECTION cs; +}; + +typedef std::condition_variable_any ConditionVariable; + +#else // Default case: use STL classes + +typedef std::mutex Mutex; +typedef std::condition_variable ConditionVariable; + +#endif + +#endif // #ifndef THREAD_WIN32_H_INCLUDED diff --git a/src/timeman.cpp b/src/timeman.cpp new file mode 100644 index 0000000..035fe33 --- /dev/null +++ b/src/timeman.cpp @@ -0,0 +1,132 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include + +#include "search.h" +#include "timeman.h" +#include "uci.h" + +TimeManagement Time; // Our global time management object + +namespace { + + enum TimeType { OptimumTime, MaxTime }; + + const int MoveHorizon = 50; // Plan time management at most this many moves ahead + const double MaxRatio = 7.09; // When in trouble, we can step over reserved time with this ratio + const double StealRatio = 0.35; // However we must not steal time from remaining moves over this ratio + + + // move_importance() is a skew-logistic function based on naive statistical + // analysis of "how many games are still undecided after n half-moves". Game + // is considered "undecided" as long as neither side has >275cp advantage. + // Data was extracted from the CCRL game database with some simple filtering criteria. + + double move_importance(int ply) { + + const double XScale = 7.64; + const double XShift = 58.4; + const double Skew = 0.183; + + return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero + } + + template + int remaining(int myTime, int movesToGo, int ply, int slowMover) { + + const double TMaxRatio = (T == OptimumTime ? 1 : MaxRatio); + const double TStealRatio = (T == OptimumTime ? 0 : StealRatio); + + double moveImportance = (move_importance(ply) * slowMover) / 100; + double otherMovesImportance = 0; + + for (int i = 1; i < movesToGo; ++i) + otherMovesImportance += move_importance(ply + 2 * i); + + double ratio1 = (TMaxRatio * moveImportance) / (TMaxRatio * moveImportance + otherMovesImportance); + double ratio2 = (moveImportance + TStealRatio * otherMovesImportance) / (moveImportance + otherMovesImportance); + + return int(myTime * std::min(ratio1, ratio2)); // Intel C++ asks for an explicit cast + } + +} // namespace + + +/// init() is called at the beginning of the search and calculates the allowed +/// thinking time out of the time control and current game ply. We support four +/// different kinds of time controls, passed in 'limits': +/// +/// inc == 0 && movestogo == 0 means: x basetime [sudden death!] +/// inc == 0 && movestogo != 0 means: x moves in y minutes +/// inc > 0 && movestogo == 0 means: x basetime + z increment +/// inc > 0 && movestogo != 0 means: x moves in y minutes + z increment + +void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) { + + int minThinkingTime = Options["Minimum Thinking Time"]; + int moveOverhead = Options["Move Overhead"]; + int slowMover = Options["Slow Mover"]; + int npmsec = Options["nodestime"]; + + // If we have to play in 'nodes as time' mode, then convert from time + // to nodes, and use resulting values in time management formulas. + // WARNING: Given npms (nodes per millisecond) must be much lower then + // the real engine speed to avoid time losses. + if (npmsec) + { + if (!availableNodes) // Only once at game start + availableNodes = npmsec * limits.time[us]; // Time is in msec + + // Convert from millisecs to nodes + limits.time[us] = (int)availableNodes; + limits.inc[us] *= npmsec; + limits.npmsec = npmsec; + } + + startTime = limits.startTime; + optimumTime = maximumTime = std::max(limits.time[us], minThinkingTime); + + const int MaxMTG = limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon; + + // We calculate optimum time usage for different hypothetical "moves to go"-values + // and choose the minimum of calculated search time values. Usually the greatest + // hypMTG gives the minimum values. + for (int hypMTG = 1; hypMTG <= MaxMTG; ++hypMTG) + { + // Calculate thinking time for hypothetical "moves to go"-value + int hypMyTime = limits.time[us] + + limits.inc[us] * (hypMTG - 1) + - moveOverhead * (2 + std::min(hypMTG, 40)); + + hypMyTime = std::max(hypMyTime, 0); + + int t1 = minThinkingTime + remaining(hypMyTime, hypMTG, ply, slowMover); + int t2 = minThinkingTime + remaining(hypMyTime, hypMTG, ply, slowMover); + + optimumTime = std::min(t1, optimumTime); + maximumTime = std::min(t2, maximumTime); + } + + if (Options["Ponder"]) + optimumTime += optimumTime / 4; +} diff --git a/src/timeman.h b/src/timeman.h new file mode 100644 index 0000000..f4e3a95 --- /dev/null +++ b/src/timeman.h @@ -0,0 +1,48 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef TIMEMAN_H_INCLUDED +#define TIMEMAN_H_INCLUDED + +#include "misc.h" +#include "search.h" +#include "thread.h" + +/// The TimeManagement class computes the optimal time to think depending on +/// the maximum available time, the game move number and other parameters. + +class TimeManagement { +public: + void init(Search::LimitsType& limits, Color us, int ply); + int optimum() const { return optimumTime; } + int maximum() const { return maximumTime; } + int elapsed() const { return int(Search::Limits.npmsec ? Threads.nodes_searched() : now() - startTime); } + + int64_t availableNodes; // When in 'nodes as time' mode + +private: + TimePoint startTime; + int optimumTime; + int maximumTime; +}; + +extern TimeManagement Time; + +#endif // #ifndef TIMEMAN_H_INCLUDED diff --git a/src/tt.cpp b/src/tt.cpp new file mode 100644 index 0000000..25f1cd0 --- /dev/null +++ b/src/tt.cpp @@ -0,0 +1,118 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include // For std::memset +#include + +#include "bitboard.h" +#include "tt.h" + +TranspositionTable TT; // Our global transposition table + + +/// TranspositionTable::resize() sets the size of the transposition table, +/// measured in megabytes. Transposition table consists of a power of 2 number +/// of clusters and each cluster consists of ClusterSize number of TTEntry. + +void TranspositionTable::resize(size_t mbSize) { + + size_t newClusterCount = mbSize * 1024 * 1024 / sizeof(Cluster); + + if (newClusterCount == clusterCount) + return; + + clusterCount = newClusterCount; + + free(mem); + mem = malloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1); + + if (!mem) + { + std::cerr << "Failed to allocate " << mbSize + << "MB for transposition table." << std::endl; + exit(EXIT_FAILURE); + } + + table = (Cluster*)((uintptr_t(mem) + CacheLineSize - 1) & ~(CacheLineSize - 1)); + clear(); +} + + +/// TranspositionTable::clear() overwrites the entire transposition table +/// with zeros. It is called whenever the table is resized, or when the +/// user asks the program to clear the table (from the UCI interface). + +void TranspositionTable::clear() { + + std::memset(table, 0, clusterCount * sizeof(Cluster)); +} + + +/// TranspositionTable::probe() looks up the current position in the transposition +/// table. It returns true and a pointer to the TTEntry if the position is found. +/// Otherwise, it returns false and a pointer to an empty or least valuable TTEntry +/// to be replaced later. The replace value of an entry is calculated as its depth +/// minus 8 times its relative age. TTEntry t1 is considered more valuable than +/// TTEntry t2 if its replace value is greater than that of t2. + +TTEntry* TranspositionTable::probe(const Key key, bool& found) const { + + TTEntry* const tte = first_entry(key); + const uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster + + for (int i = 0; i < ClusterSize; ++i) + if (!tte[i].key16 || tte[i].key16 == key16) + { + if ((tte[i].genBound8 & 0xFC) != generation8 && tte[i].key16) + tte[i].genBound8 = uint8_t(generation8 | tte[i].bound()); // Refresh + + return found = (bool)tte[i].key16, &tte[i]; + } + + // Find an entry to be replaced according to the replacement strategy + TTEntry* replace = tte; + for (int i = 1; i < ClusterSize; ++i) + // Due to our packed storage format for generation and its cyclic + // nature we add 259 (256 is the modulus plus 3 to keep the lowest + // two bound bits from affecting the result) to calculate the entry + // age correctly even after generation8 overflows into the next cycle. + if ( replace->depth8 - ((259 + generation8 - replace->genBound8) & 0xFC) * 2 + > tte[i].depth8 - ((259 + generation8 - tte[i].genBound8) & 0xFC) * 2) + replace = &tte[i]; + + return found = false, replace; +} + + +/// TranspositionTable::hashfull() returns an approximation of the hashtable +/// occupation during a search. The hash is x permill full, as per UCI protocol. + +int TranspositionTable::hashfull() const { + + int cnt = 0; + for (int i = 0; i < 1000 / ClusterSize; i++) + { + const TTEntry* tte = &table[i].entry[0]; + for (int j = 0; j < ClusterSize; j++) + if ((tte[j].genBound8 & 0xFC) == generation8) + cnt++; + } + return cnt; +} diff --git a/src/tt.h b/src/tt.h new file mode 100644 index 0000000..ca7dfbf --- /dev/null +++ b/src/tt.h @@ -0,0 +1,121 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef TT_H_INCLUDED +#define TT_H_INCLUDED + +#include "misc.h" +#include "types.h" + +/// TTEntry struct is the 10 bytes transposition table entry, defined as below: +/// +/// key 16 bit +/// move 16 bit +/// value 16 bit +/// eval value 16 bit +/// generation 6 bit +/// bound type 2 bit +/// depth 8 bit + +struct TTEntry { + + Move move() const { return (Move )move16; } + Value value() const { return (Value)value16; } + Value eval() const { return (Value)eval16; } + Depth depth() const { return (Depth)(depth8 * int(ONE_PLY)); } + Bound bound() const { return (Bound)(genBound8 & 0x3); } + + void save(Key k, Value v, Bound b, Depth d, Move m, Value ev, uint8_t g) { + + assert(d / ONE_PLY * ONE_PLY == d); + + // Preserve any existing move for the same position + if (m || (k >> 48) != key16) + move16 = (uint16_t)m; + + // Don't overwrite more valuable entries + if ( (k >> 48) != key16 + || d / ONE_PLY > depth8 - 4 + /* || g != (genBound8 & 0xFC) // Matching non-zero keys are already refreshed by probe() */ + || b == BOUND_EXACT) + { + key16 = (uint16_t)(k >> 48); + value16 = (int16_t)v; + eval16 = (int16_t)ev; + genBound8 = (uint8_t)(g | b); + depth8 = (int8_t)(d / ONE_PLY); + } + } + +private: + friend class TranspositionTable; + + uint16_t key16; + uint16_t move16; + int16_t value16; + int16_t eval16; + uint8_t genBound8; + int8_t depth8; +}; + + +/// A TranspositionTable consists of a power of 2 number of clusters and each +/// cluster consists of ClusterSize number of TTEntry. Each non-empty entry +/// contains information of exactly one position. The size of a cluster should +/// divide the size of a cache line size, to ensure that clusters never cross +/// cache lines. This ensures best cache performance, as the cacheline is +/// prefetched, as soon as possible. + +class TranspositionTable { + + static const int CacheLineSize = 64; + static const int ClusterSize = 3; + + struct Cluster { + TTEntry entry[ClusterSize]; + char padding[2]; // Align to a divisor of the cache line size + }; + + static_assert(CacheLineSize % sizeof(Cluster) == 0, "Cluster size incorrect"); + +public: + ~TranspositionTable() { free(mem); } + void new_search() { generation8 += 4; } // Lower 2 bits are used by Bound + uint8_t generation() const { return generation8; } + TTEntry* probe(const Key key, bool& found) const; + int hashfull() const; + void resize(size_t mbSize); + void clear(); + + // The 32 lowest order bits of the key are used to get the index of the cluster + TTEntry* first_entry(const Key key) const { + return &table[(uint32_t(key) * uint64_t(clusterCount)) >> 32].entry[0]; + } + +private: + size_t clusterCount; + Cluster* table; + void* mem; + uint8_t generation8; // Size must be not bigger than TTEntry::genBound8 +}; + +extern TranspositionTable TT; + +#endif // #ifndef TT_H_INCLUDED diff --git a/src/types.h b/src/types.h new file mode 100644 index 0000000..009a933 --- /dev/null +++ b/src/types.h @@ -0,0 +1,466 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef TYPES_H_INCLUDED +#define TYPES_H_INCLUDED + +/// When compiling with provided Makefile (e.g. for Linux and OSX), configuration +/// is done automatically. To get started type 'make help'. +/// +/// When Makefile is not used (e.g. with Microsoft Visual Studio) some switches +/// need to be set manually: +/// +/// -DNDEBUG | Disable debugging mode. Always use this for release. +/// +/// -DNO_PREFETCH | Disable use of prefetch asm-instruction. You may need this to +/// | run on some very old machines. +/// +/// -DUSE_POPCNT | Add runtime support for use of popcnt asm-instruction. Works +/// | only in 64-bit mode and requires hardware with popcnt support. +/// +/// -DUSE_PEXT | Add runtime support for use of pext asm-instruction. Works +/// | only in 64-bit mode and requires hardware with pext support. + +#include +#include +#include +#include +#include + +#if defined(_MSC_VER) +// Disable some silly and noisy warning from MSVC compiler +#pragma warning(disable: 4127) // Conditional expression is constant +#pragma warning(disable: 4146) // Unary minus operator applied to unsigned type +#pragma warning(disable: 4800) // Forcing value to bool 'true' or 'false' +#endif + +/// Predefined macros hell: +/// +/// __GNUC__ Compiler is gcc, Clang or Intel on Linux +/// __INTEL_COMPILER Compiler is Intel +/// _MSC_VER Compiler is MSVC or Intel on Windows +/// _WIN32 Building on Windows (any) +/// _WIN64 Building on Windows 64 bit + +#if defined(_WIN64) && defined(_MSC_VER) // No Makefile used +# include // Microsoft header for _BitScanForward64() +# define IS_64BIT +#endif + +#if defined(USE_POPCNT) && (defined(__INTEL_COMPILER) || defined(_MSC_VER)) +# include // Intel and Microsoft header for _mm_popcnt_u64() +#endif + +#if !defined(NO_PREFETCH) && (defined(__INTEL_COMPILER) || defined(_MSC_VER)) +# include // Intel and Microsoft header for _mm_prefetch() +#endif + +#if defined(USE_PEXT) +# include // Header for _pext_u64() intrinsic +# define pext(b, m) _pext_u64(b, m) +#else +# define pext(b, m) 0 +#endif + +#ifdef USE_POPCNT +const bool HasPopCnt = true; +#else +const bool HasPopCnt = false; +#endif + +#ifdef USE_PEXT +const bool HasPext = true; +#else +const bool HasPext = false; +#endif + +#ifdef IS_64BIT +const bool Is64Bit = true; +#else +const bool Is64Bit = false; +#endif + +typedef uint64_t Key; +typedef uint64_t Bitboard; + +const int MAX_MOVES = 256; +const int MAX_PLY = 128; + +/// A move needs 16 bits to be stored +/// +/// bit 0- 5: destination square (from 0 to 63) +/// bit 6-11: origin square (from 0 to 63) +/// bit 12-13: promotion piece type - 2 (from KNIGHT-2 to QUEEN-2) +/// bit 14-15: special move flag: promotion (1), en passant (2), castling (3) +/// NOTE: EN-PASSANT bit is set only when a pawn can be captured +/// +/// Special cases are MOVE_NONE and MOVE_NULL. We can sneak these in because in +/// any normal move destination square is always different from origin square +/// while MOVE_NONE and MOVE_NULL have the same origin and destination square. + +enum Move : int { + MOVE_NONE, + MOVE_NULL = 65 +}; + +enum MoveType { + NORMAL, + PROMOTION = 1 << 14, + ENPASSANT = 2 << 14, + CASTLING = 3 << 14 +}; + +enum Color { + WHITE, BLACK, COLOR_NB = 2 +}; + +enum CastlingSide { + KING_SIDE, QUEEN_SIDE, CASTLING_SIDE_NB = 2 +}; + +enum CastlingRight { + NO_CASTLING, + WHITE_OO, + WHITE_OOO = WHITE_OO << 1, + BLACK_OO = WHITE_OO << 2, + BLACK_OOO = WHITE_OO << 3, + ANY_CASTLING = WHITE_OO | WHITE_OOO | BLACK_OO | BLACK_OOO, + CASTLING_RIGHT_NB = 16 +}; + +template struct MakeCastling { + static constexpr CastlingRight + right = C == WHITE ? S == QUEEN_SIDE ? WHITE_OOO : WHITE_OO + : S == QUEEN_SIDE ? BLACK_OOO : BLACK_OO; +}; + +enum Phase { + PHASE_ENDGAME, + PHASE_MIDGAME = 128, + MG = 0, EG = 1, PHASE_NB = 2 +}; + +enum ScaleFactor { + SCALE_FACTOR_DRAW = 0, + SCALE_FACTOR_ONEPAWN = 48, + SCALE_FACTOR_NORMAL = 64, + SCALE_FACTOR_MAX = 128, + SCALE_FACTOR_NONE = 255 +}; + +enum Bound { + BOUND_NONE, + BOUND_UPPER, + BOUND_LOWER, + BOUND_EXACT = BOUND_UPPER | BOUND_LOWER +}; + +enum Value : int { + VALUE_ZERO = 0, + VALUE_DRAW = 0, + VALUE_KNOWN_WIN = 10000, + VALUE_MATE = 32000, + VALUE_INFINITE = 32001, + VALUE_NONE = 32002, + + VALUE_MATE_IN_MAX_PLY = VALUE_MATE - 2 * MAX_PLY, + VALUE_MATED_IN_MAX_PLY = -VALUE_MATE + 2 * MAX_PLY, + + PawnValueMg = 171, PawnValueEg = 240, + KnightValueMg = 764, KnightValueEg = 848, + BishopValueMg = 826, BishopValueEg = 891, + RookValueMg = 1282, RookValueEg = 1373, + QueenValueMg = 2526, QueenValueEg = 2646, + + MidgameLimit = 15258, EndgameLimit = 3915 +}; + +enum PieceType { + NO_PIECE_TYPE, PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING, + ALL_PIECES = 0, + QUEEN_DIAGONAL = 7, + PIECE_TYPE_NB = 8 +}; + +enum Piece { + NO_PIECE, + W_PAWN = 1, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING, + B_PAWN = 9, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING, + PIECE_NB = 16 +}; + +extern Value PieceValue[PHASE_NB][PIECE_NB]; + +enum Depth : int { + + ONE_PLY = 1, + + DEPTH_ZERO = 0 * ONE_PLY, + DEPTH_QS_CHECKS = 0 * ONE_PLY, + DEPTH_QS_NO_CHECKS = -1 * ONE_PLY, + DEPTH_QS_RECAPTURES = -5 * ONE_PLY, + + DEPTH_NONE = -6 * ONE_PLY, + DEPTH_MAX = MAX_PLY * ONE_PLY +}; + +static_assert(!(ONE_PLY & (ONE_PLY - 1)), "ONE_PLY is not a power of 2"); + +enum Square : int { + SQ_A1, SQ_B1, SQ_C1, SQ_D1, SQ_E1, SQ_F1, SQ_G1, SQ_H1, + SQ_A2, SQ_B2, SQ_C2, SQ_D2, SQ_E2, SQ_F2, SQ_G2, SQ_H2, + SQ_A3, SQ_B3, SQ_C3, SQ_D3, SQ_E3, SQ_F3, SQ_G3, SQ_H3, + SQ_A4, SQ_B4, SQ_C4, SQ_D4, SQ_E4, SQ_F4, SQ_G4, SQ_H4, + SQ_A5, SQ_B5, SQ_C5, SQ_D5, SQ_E5, SQ_F5, SQ_G5, SQ_H5, + SQ_A6, SQ_B6, SQ_C6, SQ_D6, SQ_E6, SQ_F6, SQ_G6, SQ_H6, + SQ_A7, SQ_B7, SQ_C7, SQ_D7, SQ_E7, SQ_F7, SQ_G7, SQ_H7, + SQ_A8, SQ_B8, SQ_C8, SQ_D8, SQ_E8, SQ_F8, SQ_G8, SQ_H8, + SQ_NONE, + + SQUARE_NB = 64 +}; + +enum Direction : int { + NORTH = 8, + EAST = 1, + SOUTH = -NORTH, + WEST = -EAST, + + NORTH_EAST = NORTH + EAST, + SOUTH_EAST = SOUTH + EAST, + SOUTH_WEST = SOUTH + WEST, + NORTH_WEST = NORTH + WEST +}; + +enum File : int { + FILE_A, FILE_B, FILE_C, FILE_D, FILE_E, FILE_F, FILE_G, FILE_H, FILE_NB +}; + +enum Rank : int { + RANK_1, RANK_2, RANK_3, RANK_4, RANK_5, RANK_6, RANK_7, RANK_8, RANK_NB +}; + + +/// Score enum stores a middlegame and an endgame value in a single integer +/// (enum). The least significant 16 bits are used to store the endgame value +/// and the upper 16 bits are used to store the middlegame value. Take some +/// care to avoid left-shifting a signed int to avoid undefined behavior. +enum Score : int { SCORE_ZERO }; + +constexpr Score make_score(int mg, int eg) { + return Score((int)((unsigned int)eg << 16) + mg); +} + +/// Extracting the signed lower and upper 16 bits is not so trivial because +/// according to the standard a simple cast to short is implementation defined +/// and so is a right shift of a signed integer. +inline Value eg_value(Score s) { + union { uint16_t u; int16_t s; } eg = { uint16_t(unsigned(s + 0x8000) >> 16) }; + return Value(eg.s); +} + +inline Value mg_value(Score s) { + union { uint16_t u; int16_t s; } mg = { uint16_t(unsigned(s)) }; + return Value(mg.s); +} + +#define ENABLE_BASE_OPERATORS_ON(T) \ +constexpr T operator+(T d1, T d2) { return T(int(d1) + int(d2)); } \ +constexpr T operator-(T d1, T d2) { return T(int(d1) - int(d2)); } \ +constexpr T operator-(T d) { return T(-int(d)); } \ +inline T& operator+=(T& d1, T d2) { return d1 = d1 + d2; } \ +inline T& operator-=(T& d1, T d2) { return d1 = d1 - d2; } + +#define ENABLE_INCR_OPERATORS_ON(T) \ +inline T& operator++(T& d) { return d = T(int(d) + 1); } \ +inline T& operator--(T& d) { return d = T(int(d) - 1); } + +#define ENABLE_FULL_OPERATORS_ON(T) \ +ENABLE_BASE_OPERATORS_ON(T) \ +ENABLE_INCR_OPERATORS_ON(T) \ +constexpr T operator*(int i, T d) { return T(i * int(d)); } \ +constexpr T operator*(T d, int i) { return T(int(d) * i); } \ +constexpr T operator/(T d, int i) { return T(int(d) / i); } \ +constexpr int operator/(T d1, T d2) { return int(d1) / int(d2); } \ +inline T& operator*=(T& d, int i) { return d = T(int(d) * i); } \ +inline T& operator/=(T& d, int i) { return d = T(int(d) / i); } + +ENABLE_FULL_OPERATORS_ON(Value) +ENABLE_FULL_OPERATORS_ON(Depth) +ENABLE_FULL_OPERATORS_ON(Direction) + +ENABLE_INCR_OPERATORS_ON(PieceType) +ENABLE_INCR_OPERATORS_ON(Piece) +ENABLE_INCR_OPERATORS_ON(Color) +ENABLE_INCR_OPERATORS_ON(Square) +ENABLE_INCR_OPERATORS_ON(File) +ENABLE_INCR_OPERATORS_ON(Rank) + +ENABLE_BASE_OPERATORS_ON(Score) + +#undef ENABLE_FULL_OPERATORS_ON +#undef ENABLE_INCR_OPERATORS_ON +#undef ENABLE_BASE_OPERATORS_ON + +/// Additional operators to add integers to a Value +constexpr Value operator+(Value v, int i) { return Value(int(v) + i); } +constexpr Value operator-(Value v, int i) { return Value(int(v) - i); } +inline Value& operator+=(Value& v, int i) { return v = v + i; } +inline Value& operator-=(Value& v, int i) { return v = v - i; } + +/// Additional operators to add a Direction to a Square +inline Square operator+(Square s, Direction d) { return Square(int(s) + int(d)); } +inline Square operator-(Square s, Direction d) { return Square(int(s) - int(d)); } +inline Square& operator+=(Square &s, Direction d) { return s = s + d; } +inline Square& operator-=(Square &s, Direction d) { return s = s - d; } + +/// Only declared but not defined. We don't want to multiply two scores due to +/// a very high risk of overflow. So user should explicitly convert to integer. +Score operator*(Score, Score) = delete; + +/// Division of a Score must be handled separately for each term +inline Score operator/(Score s, int i) { + return make_score(mg_value(s) / i, eg_value(s) / i); +} + +/// Multiplication of a Score by an integer. We check for overflow in debug mode. +inline Score operator*(Score s, int i) { + + Score result = Score(int(s) * i); + + assert(eg_value(result) == (i * eg_value(s))); + assert(mg_value(result) == (i * mg_value(s))); + assert((i == 0) || (result / i) == s ); + + return result; +} + +constexpr Color operator~(Color c) { + return Color(c ^ BLACK); // Toggle color +} + +constexpr Square operator~(Square s) { + return Square(s ^ SQ_A8); // Vertical flip SQ_A1 -> SQ_A8 +} + +constexpr File operator~(File f) { + return File(f ^ FILE_H); // Horizontal flip FILE_A -> FILE_H +} + +constexpr Piece operator~(Piece pc) { + return Piece(pc ^ 8); // Swap color of piece B_KNIGHT -> W_KNIGHT +} + +constexpr CastlingRight operator|(Color c, CastlingSide s) { + return CastlingRight(WHITE_OO << ((s == QUEEN_SIDE) + 2 * c)); +} + +constexpr Value mate_in(int ply) { + return VALUE_MATE - ply; +} + +constexpr Value mated_in(int ply) { + return -VALUE_MATE + ply; +} + +constexpr Square make_square(File f, Rank r) { + return Square((r << 3) + f); +} + +constexpr Piece make_piece(Color c, PieceType pt) { + return Piece((c << 3) + pt); +} + +constexpr PieceType type_of(Piece pc) { + return PieceType(pc & 7); +} + +inline Color color_of(Piece pc) { + assert(pc != NO_PIECE); + return Color(pc >> 3); +} + +constexpr bool is_ok(Square s) { + return s >= SQ_A1 && s <= SQ_H8; +} + +constexpr File file_of(Square s) { + return File(s & 7); +} + +constexpr Rank rank_of(Square s) { + return Rank(s >> 3); +} + +constexpr Square relative_square(Color c, Square s) { + return Square(s ^ (c * 56)); +} + +constexpr Rank relative_rank(Color c, Rank r) { + return Rank(r ^ (c * 7)); +} + +constexpr Rank relative_rank(Color c, Square s) { + return relative_rank(c, rank_of(s)); +} + +inline bool opposite_colors(Square s1, Square s2) { + int s = int(s1) ^ int(s2); + return ((s >> 3) ^ s) & 1; +} + +constexpr Direction pawn_push(Color c) { + return c == WHITE ? NORTH : SOUTH; +} + +constexpr Square from_sq(Move m) { + return Square((m >> 6) & 0x3F); +} + +constexpr Square to_sq(Move m) { + return Square(m & 0x3F); +} + +constexpr int from_to(Move m) { + return m & 0xFFF; +} + +constexpr MoveType type_of(Move m) { + return MoveType(m & (3 << 14)); +} + +constexpr PieceType promotion_type(Move m) { + return PieceType(((m >> 12) & 3) + KNIGHT); +} + +inline Move make_move(Square from, Square to) { + return Move((from << 6) + to); +} + +template +constexpr Move make(Square from, Square to, PieceType pt = KNIGHT) { + return Move(T + ((pt - KNIGHT) << 12) + (from << 6) + to); +} + +constexpr bool is_ok(Move m) { + return from_sq(m) != to_sq(m); // Catch MOVE_NULL and MOVE_NONE +} + +#endif // #ifndef TYPES_H_INCLUDED diff --git a/src/uci.cpp b/src/uci.cpp new file mode 100644 index 0000000..adba98d --- /dev/null +++ b/src/uci.cpp @@ -0,0 +1,316 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include +#include + +#include "evaluate.h" +#include "movegen.h" +#include "position.h" +#include "search.h" +#include "thread.h" +#include "tt.h" +#include "timeman.h" +#include "uci.h" +#include "syzygy/tbprobe.h" + +using namespace std; + +extern vector setup_bench(const Position&, istream&); + +namespace { + + // FEN string of the initial position, normal chess + const char* StartFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"; + + + // position() is called when engine receives the "position" UCI command. + // The function sets up the position described in the given FEN string ("fen") + // or the starting position ("startpos") and then makes the moves given in the + // following move list ("moves"). + + void position(Position& pos, istringstream& is, StateListPtr& states) { + + Move m; + string token, fen; + + is >> token; + + if (token == "startpos") + { + fen = StartFEN; + is >> token; // Consume "moves" token if any + } + else if (token == "fen") + while (is >> token && token != "moves") + fen += token + " "; + else + return; + + states = StateListPtr(new std::deque(1)); // Drop old and create a new one + pos.set(fen, Options["UCI_Chess960"], &states->back(), Threads.main()); + + // Parse move list (if any) + while (is >> token && (m = UCI::to_move(pos, token)) != MOVE_NONE) + { + states->emplace_back(); + pos.do_move(m, states->back()); + } + } + + + // setoption() is called when engine receives the "setoption" UCI command. The + // function updates the UCI option ("name") to the given value ("value"). + + void setoption(istringstream& is) { + + string token, name, value; + + is >> token; // Consume "name" token + + // Read option name (can contain spaces) + while (is >> token && token != "value") + name += string(" ", name.empty() ? 0 : 1) + token; + + // Read option value (can contain spaces) + while (is >> token) + value += string(" ", value.empty() ? 0 : 1) + token; + + if (Options.count(name)) + Options[name] = value; + else + sync_cout << "No such option: " << name << sync_endl; + } + + + // go() is called when engine receives the "go" UCI command. The function sets + // the thinking time and other parameters from the input string, then starts + // the search. + + void go(Position& pos, istringstream& is, StateListPtr& states) { + + Search::LimitsType limits; + string token; + bool ponderMode = false; + + limits.startTime = now(); // As early as possible! + + while (is >> token) + if (token == "searchmoves") + while (is >> token) + limits.searchmoves.push_back(UCI::to_move(pos, token)); + + else if (token == "wtime") is >> limits.time[WHITE]; + else if (token == "btime") is >> limits.time[BLACK]; + else if (token == "winc") is >> limits.inc[WHITE]; + else if (token == "binc") is >> limits.inc[BLACK]; + else if (token == "movestogo") is >> limits.movestogo; + else if (token == "depth") is >> limits.depth; + else if (token == "nodes") is >> limits.nodes; + else if (token == "movetime") is >> limits.movetime; + else if (token == "mate") is >> limits.mate; + else if (token == "perft") is >> limits.perft; + else if (token == "infinite") limits.infinite = 1; + else if (token == "ponder") ponderMode = true; + + Threads.start_thinking(pos, states, limits, ponderMode); + } + + + // bench() is called when engine receives the "bench" command. Firstly + // a list of UCI commands is setup according to bench parameters, then + // it is run one by one printing a summary at the end. + + void bench(Position& pos, istream& args, StateListPtr& states) { + + string token; + uint64_t num, nodes = 0, cnt = 1; + + vector list = setup_bench(pos, args); + num = count_if(list.begin(), list.end(), [](string s) { return s.find("go ") == 0; }); + + TimePoint elapsed = now(); + + for (const auto& cmd : list) + { + istringstream is(cmd); + is >> skipws >> token; + + if (token == "go") + { + cerr << "\nPosition: " << cnt++ << '/' << num << endl; + go(pos, is, states); + Threads.main()->wait_for_search_finished(); + nodes += Threads.nodes_searched(); + } + else if (token == "setoption") setoption(is); + else if (token == "position") position(pos, is, states); + else if (token == "ucinewgame") Search::clear(); + } + + elapsed = now() - elapsed + 1; // Ensure positivity to avoid a 'divide by zero' + + dbg_print(); // Just before exiting + + cerr << "\n===========================" + << "\nTotal time (ms) : " << elapsed + << "\nNodes searched : " << nodes + << "\nNodes/second : " << 1000 * nodes / elapsed << endl; + } + +} // namespace + + +/// UCI::loop() waits for a command from stdin, parses it and calls the appropriate +/// function. Also intercepts EOF from stdin to ensure gracefully exiting if the +/// GUI dies unexpectedly. When called with some command line arguments, e.g. to +/// run 'bench', once the command is executed the function returns immediately. +/// In addition to the UCI ones, also some additional debug commands are supported. + +void UCI::loop(int argc, char* argv[]) { + + Position pos; + string token, cmd; + StateListPtr states(new std::deque(1)); + auto uiThread = std::make_shared(0); + + pos.set(StartFEN, false, &states->back(), uiThread.get()); + + for (int i = 1; i < argc; ++i) + cmd += std::string(argv[i]) + " "; + + do { + if (argc == 1 && !getline(cin, cmd)) // Block here waiting for input or EOF + cmd = "quit"; + + istringstream is(cmd); + + token.clear(); // Avoid a stale if getline() returns empty or blank line + is >> skipws >> token; + + // The GUI sends 'ponderhit' to tell us the user has played the expected move. + // So 'ponderhit' will be sent if we were told to ponder on the same move the + // user has played. We should continue searching but switch from pondering to + // normal search. In case Threads.stopOnPonderhit is set we are waiting for + // 'ponderhit' to stop the search, for instance if max search depth is reached. + if ( token == "quit" + || token == "stop" + || (token == "ponderhit" && Threads.stopOnPonderhit)) + Threads.stop = true; + + else if (token == "ponderhit") + Threads.ponder = false; // Switch to normal search + + else if (token == "uci") + sync_cout << "id name " << engine_info(true) + << "\n" << Options + << "\nuciok" << sync_endl; + + else if (token == "setoption") setoption(is); + else if (token == "go") go(pos, is, states); + else if (token == "position") position(pos, is, states); + else if (token == "ucinewgame") Search::clear(); + else if (token == "isready") sync_cout << "readyok" << sync_endl; + + // Additional custom non-UCI commands, mainly for debugging + else if (token == "flip") pos.flip(); + else if (token == "bench") bench(pos, is, states); + else if (token == "d") sync_cout << pos << sync_endl; + else if (token == "eval") sync_cout << Eval::trace(pos) << sync_endl; + else + sync_cout << "Unknown command: " << cmd << sync_endl; + + } while (token != "quit" && argc == 1); // Command line args are one-shot +} + + +/// UCI::value() converts a Value to a string suitable for use with the UCI +/// protocol specification: +/// +/// cp The score from the engine's point of view in centipawns. +/// mate Mate in y moves, not plies. If the engine is getting mated +/// use negative values for y. + +string UCI::value(Value v) { + + assert(-VALUE_INFINITE < v && v < VALUE_INFINITE); + + stringstream ss; + + if (abs(v) < VALUE_MATE - MAX_PLY) + ss << "cp " << v * 100 / PawnValueEg; + else + ss << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2; + + return ss.str(); +} + + +/// UCI::square() converts a Square to a string in algebraic notation (g1, a7, etc.) + +std::string UCI::square(Square s) { + return std::string{ char('a' + file_of(s)), char('1' + rank_of(s)) }; +} + + +/// UCI::move() converts a Move to a string in coordinate notation (g1f3, a7a8q). +/// The only special case is castling, where we print in the e1g1 notation in +/// normal chess mode, and in e1h1 notation in chess960 mode. Internally all +/// castling moves are always encoded as 'king captures rook'. + +string UCI::move(Move m, bool chess960) { + + Square from = from_sq(m); + Square to = to_sq(m); + + if (m == MOVE_NONE) + return "(none)"; + + if (m == MOVE_NULL) + return "0000"; + + if (type_of(m) == CASTLING && !chess960) + to = make_square(to > from ? FILE_G : FILE_C, rank_of(from)); + + string move = UCI::square(from) + UCI::square(to); + + if (type_of(m) == PROMOTION) + move += " pnbrqk"[promotion_type(m)]; + + return move; +} + + +/// UCI::to_move() converts a string representing a move in coordinate notation +/// (g1f3, a7a8q) to the corresponding legal Move, if any. + +Move UCI::to_move(const Position& pos, string& str) { + + if (str.length() == 5) // Junior could send promotion piece in uppercase + str[4] = char(tolower(str[4])); + + for (const auto& m : MoveList(pos)) + if (str == UCI::move(m, pos.is_chess960())) + return m; + + return MOVE_NONE; +} diff --git a/src/uci.h b/src/uci.h new file mode 100644 index 0000000..0b3550b --- /dev/null +++ b/src/uci.h @@ -0,0 +1,80 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#ifndef UCI_H_INCLUDED +#define UCI_H_INCLUDED + +#include +#include + +#include "types.h" + +class Position; + +namespace UCI { + +class Option; + +/// Custom comparator because UCI options should be case insensitive +struct CaseInsensitiveLess { + bool operator() (const std::string&, const std::string&) const; +}; + +/// Our options container is actually a std::map +typedef std::map OptionsMap; + +/// Option class implements an option as defined by UCI protocol +class Option { + + typedef void (*OnChange)(const Option&); + +public: + Option(OnChange = nullptr); + Option(bool v, OnChange = nullptr); + Option(const char* v, OnChange = nullptr); + Option(int v, int minv, int maxv, OnChange = nullptr); + + Option& operator=(const std::string&); + void operator<<(const Option&); + operator int() const; + operator std::string() const; + +private: + friend std::ostream& operator<<(std::ostream&, const OptionsMap&); + + std::string defaultValue, currentValue, type; + int min, max; + size_t idx; + OnChange on_change; +}; + +void init(OptionsMap&); +void loop(int argc, char* argv[]); +std::string value(Value v); +std::string square(Square s); +std::string move(Move m, bool chess960); +std::string pv(const Position& pos, Depth depth, Value alpha, Value beta); +Move to_move(const Position& pos, std::string& str); + +} // namespace UCI + +extern UCI::OptionsMap Options; + +#endif // #ifndef UCI_H_INCLUDED diff --git a/src/ucioption.cpp b/src/ucioption.cpp new file mode 100644 index 0000000..87ebaa8 --- /dev/null +++ b/src/ucioption.cpp @@ -0,0 +1,164 @@ +/* + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + + Stockfish is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Stockfish is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include +#include +#include + +#include "misc.h" +#include "search.h" +#include "thread.h" +#include "tt.h" +#include "uci.h" +#include "syzygy/tbprobe.h" + +using std::string; + +UCI::OptionsMap Options; // Global object + +namespace UCI { + +/// 'On change' actions, triggered by an option's value change +void on_clear_hash(const Option&) { Search::clear(); } +void on_hash_size(const Option& o) { TT.resize(o); } +void on_logger(const Option& o) { start_logger(o); } +void on_threads(const Option& o) { Threads.set(o); } +void on_tb_path(const Option& o) { Tablebases::init(o); } + + +/// Our case insensitive less() function as required by UCI protocol +bool CaseInsensitiveLess::operator() (const string& s1, const string& s2) const { + + return std::lexicographical_compare(s1.begin(), s1.end(), s2.begin(), s2.end(), + [](char c1, char c2) { return tolower(c1) < tolower(c2); }); +} + + +/// init() initializes the UCI options to their hard-coded default values + +void init(OptionsMap& o) { + + // at most 2^32 clusters. + const int MaxHashMB = Is64Bit ? 131072 : 2048; + + o["Debug Log File"] << Option("", on_logger); + o["Contempt"] << Option(20, -100, 100); + o["Threads"] << Option(1, 1, 512, on_threads); + o["Hash"] << Option(16, 1, MaxHashMB, on_hash_size); + o["Clear Hash"] << Option(on_clear_hash); + o["Ponder"] << Option(false); + o["MultiPV"] << Option(1, 1, 500); + o["Skill Level"] << Option(20, 0, 20); + o["Move Overhead"] << Option(30, 0, 5000); + o["Minimum Thinking Time"] << Option(20, 0, 5000); + o["Slow Mover"] << Option(89, 10, 1000); + o["nodestime"] << Option(0, 0, 10000); + o["UCI_Chess960"] << Option(false); + o["SyzygyPath"] << Option("", on_tb_path); + o["SyzygyProbeDepth"] << Option(1, 1, 100); + o["Syzygy50MoveRule"] << Option(true); + o["SyzygyProbeLimit"] << Option(6, 0, 6); +} + + +/// operator<<() is used to print all the options default values in chronological +/// insertion order (the idx field) and in the format defined by the UCI protocol. + +std::ostream& operator<<(std::ostream& os, const OptionsMap& om) { + + for (size_t idx = 0; idx < om.size(); ++idx) + for (const auto& it : om) + if (it.second.idx == idx) + { + const Option& o = it.second; + os << "\noption name " << it.first << " type " << o.type; + + if (o.type != "button") + os << " default " << o.defaultValue; + + if (o.type == "spin") + os << " min " << o.min << " max " << o.max; + + break; + } + + return os; +} + + +/// Option class constructors and conversion operators + +Option::Option(const char* v, OnChange f) : type("string"), min(0), max(0), on_change(f) +{ defaultValue = currentValue = v; } + +Option::Option(bool v, OnChange f) : type("check"), min(0), max(0), on_change(f) +{ defaultValue = currentValue = (v ? "true" : "false"); } + +Option::Option(OnChange f) : type("button"), min(0), max(0), on_change(f) +{} + +Option::Option(int v, int minv, int maxv, OnChange f) : type("spin"), min(minv), max(maxv), on_change(f) +{ defaultValue = currentValue = std::to_string(v); } + +Option::operator int() const { + assert(type == "check" || type == "spin"); + return (type == "spin" ? stoi(currentValue) : currentValue == "true"); +} + +Option::operator std::string() const { + assert(type == "string"); + return currentValue; +} + + +/// operator<<() inits options and assigns idx in the correct printing order + +void Option::operator<<(const Option& o) { + + static size_t insert_order = 0; + + *this = o; + idx = insert_order++; +} + + +/// operator=() updates currentValue and triggers on_change() action. It's up to +/// the GUI to check for option's limits, but we could receive the new value from +/// the user by console window, so let's check the bounds anyway. + +Option& Option::operator=(const string& v) { + + assert(!type.empty()); + + if ( (type != "button" && v.empty()) + || (type == "check" && v != "true" && v != "false") + || (type == "spin" && (stoi(v) < min || stoi(v) > max))) + return *this; + + if (type != "button") + currentValue = v; + + if (on_change) + on_change(*this); + + return *this; +} + +} // namespace UCI diff --git a/tests/instrumented.sh b/tests/instrumented.sh new file mode 100755 index 0000000..2cae793 --- /dev/null +++ b/tests/instrumented.sh @@ -0,0 +1,123 @@ +#!/bin/bash +# check for errors under valgrind or sanitizers. + +error() +{ + echo "instrumented testing failed on line $1" + exit 1 +} +trap 'error ${LINENO}' ERR + +# define suitable post and prefixes for testing options +case $1 in + --valgrind) + echo "valgrind testing started" + prefix='' + exeprefix='valgrind --error-exitcode=42' + postfix='1>/dev/null' + threads="1" + ;; + --valgrind-thread) + echo "valgrind-thread testing started" + prefix='' + exeprefix='valgrind --error-exitcode=42' + postfix='1>/dev/null' + threads="2" + ;; + --sanitizer-undefined) + echo "sanitizer-undefined testing started" + prefix='!' + exeprefix='' + postfix='2>&1 | grep "runtime error:"' + threads="1" + ;; + --sanitizer-thread) + echo "sanitizer-thread testing started" + prefix='!' + exeprefix='' + postfix='2>&1 | grep "WARNING: ThreadSanitizer:"' + threads="2" + +cat << EOF > tsan.supp +race:TTEntry::move +race:TTEntry::depth +race:TTEntry::bound +race:TTEntry::save +race:TTEntry::value +race:TTEntry::eval + +race:TranspositionTable::probe +race:TranspositionTable::hashfull + +EOF + + export TSAN_OPTIONS="suppressions=./tsan.supp" + + ;; + *) + echo "unknown testing started" + prefix='' + exeprefix='' + postfix='' + threads="1" + ;; +esac + +# simple command line testing +for args in "eval" \ + "go nodes 1000" \ + "go depth 10" \ + "go movetime 1000" \ + "go wtime 8000 btime 8000 winc 500 binc 500" \ + "bench 128 $threads 10 default depth" +do + + echo "$prefix $exeprefix ./stockfish $args $postfix" + eval "$prefix $exeprefix ./stockfish $args $postfix" + +done + +# more general testing, following an uci protocol exchange +cat << EOF > game.exp + set timeout 10 + spawn $exeprefix ./stockfish + + send "uci\n" + expect "uciok" + + send "setoption name Threads value $threads\n" + + send "ucinewgame\n" + send "position startpos\n" + send "go nodes 1000\n" + expect "bestmove" + + send "position startpos moves e2e4 e7e6\n" + send "go nodes 1000\n" + expect "bestmove" + + send "position fen 5rk1/1K4p1/8/8/3B4/8/8/8 b - - 0 1\n" + send "go depth 30\n" + expect "bestmove" + + send "quit\n" + expect eof + + # return error code of the spawned program, useful for valgrind + lassign [wait] pid spawnid os_error_flag value + exit \$value +EOF + +for exps in game.exp +do + + echo "$prefix expect $exps $postfix" + eval "$prefix expect $exps $postfix" + + rm $exps + +done + +rm -f tsan.supp + +echo "instrumented testing OK" diff --git a/tests/perft.sh b/tests/perft.sh new file mode 100755 index 0000000..d402221 --- /dev/null +++ b/tests/perft.sh @@ -0,0 +1,32 @@ +#!/bin/bash +# verify perft numbers (positions from https://chessprogramming.wikispaces.com/Perft+Results) + +error() +{ + echo "perft testing failed on line $1" + exit 1 +} +trap 'error ${LINENO}' ERR + +echo "perft testing started" + +cat << EOF > perft.exp + set timeout 10 + lassign \$argv pos depth result + spawn ./stockfish + send "position \$pos\\ngo perft \$depth\\n" + expect "Nodes searched? \$result" {} timeout {exit 1} + send "quit\\n" + expect eof +EOF + +expect perft.exp startpos 5 4865609 > /dev/null +expect perft.exp "fen r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq -" 5 193690690 > /dev/null +expect perft.exp "fen 8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - -" 6 11030083 > /dev/null +expect perft.exp "fen r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1" 5 15833292 > /dev/null +expect perft.exp "fen rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8" 5 89941194 > /dev/null +expect perft.exp "fen r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10" 5 164075551 > /dev/null + +rm perft.exp + +echo "perft testing OK" diff --git a/tests/reprosearch.sh b/tests/reprosearch.sh new file mode 100755 index 0000000..9fd847f --- /dev/null +++ b/tests/reprosearch.sh @@ -0,0 +1,61 @@ +#!/bin/bash +# verify reproducible search + +error() +{ + echo "reprosearch testing failed on line $1" + exit 1 +} +trap 'error ${LINENO}' ERR + +echo "reprosearch testing started" + +# repeat two short games, separated by ucinewgame. +# with go nodes $nodes they should result in exactly +# the same node count for each iteration. +cat << EOF > repeat.exp + set timeout 10 + spawn ./stockfish + lassign \$argv nodes + + send "uci\n" + expect "uciok" + + send "ucinewgame\n" + send "position startpos\n" + send "go nodes \$nodes\n" + expect "bestmove" + + send "position startpos moves e2e4 e7e6\n" + send "go nodes \$nodes\n" + expect "bestmove" + + send "ucinewgame\n" + send "position startpos\n" + send "go nodes \$nodes\n" + expect "bestmove" + + send "position startpos moves e2e4 e7e6\n" + send "go nodes \$nodes\n" + expect "bestmove" + + send "quit\n" + expect eof +EOF + +# to increase the likelyhood of finding a non-reproducible case, +# the allowed number of nodes are varied systematically +for i in `seq 1 20` +do + + nodes=$((100*3**i/2**i)) + echo "reprosearch testing with $nodes nodes" + + # each line should appear exactly an even number of times + expect repeat.exp $nodes 2>&1 | grep -o "nodes [0-9]*" | sort | uniq -c | awk '{if ($1%2!=0) exit(1)}' + +done + +rm repeat.exp + +echo "reprosearch testing OK" diff --git a/tests/signature.sh b/tests/signature.sh new file mode 100755 index 0000000..00fd2dc --- /dev/null +++ b/tests/signature.sh @@ -0,0 +1,27 @@ +#!/bin/bash +# obtain and optionally verify Bench / signature +# if no reference is given, the output is deliberately limited to just the signature + +error() +{ + echo "running bench for signature failed on line $1" + exit 1 +} +trap 'error ${LINENO}' ERR + +# obtain + +signature=`./stockfish bench 2>&1 | grep "Nodes searched : " | awk '{print $4}'` + +if [ $# -gt 0 ]; then + # compare to given reference + if [ "$1" != "$signature" ]; then + echo "signature mismatch: reference $1 obtained $signature" + exit 1 + else + echo "signature OK: $signature" + fi +else + # just report signature + echo $signature +fi -- 2.30.2