stockfish_15.1_android_armv8.zip

<div align="center"> [![Stockfish][stockfish128-logo]][website-link] [![Build][build-badge]][build-link] [![License][license-badge]][license-link] <br> [![Release][release-badge]][release-link] [![Commits][commits-badge]][commits-link] <br> [![Website][website-badge]][website-link] [![Fishtest][fishtest-badge]][fishtest-link] [![Discord][discord-badge]][discord-link] </div> ## Overview [Stockfish][website-link] is a free, powerful UCI chess engine derived from Glaurung 2.1. Stockfish is not a complete chess program and requires a UCI-compatible graphical user interface (GUI) (e.g. XBoard with PolyGlot, Scid, Cute Chess, 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. The Stockfish engine features two evaluation functions for chess. The efficiently updatable neural network (NNUE) based evaluation is the default and by far the strongest. The classical evaluation based on handcrafted terms remains available. The strongest network is integrated in the binary and downloaded automatically during the build process. The NNUE evaluation benefits from the vector intrinsics available on most CPUs (sse2, avx2, neon, or similar). ## Files This distribution of Stockfish consists of the following files: * [README.md][readme-link], the file you are currently reading. * [Copying.txt][license-link], a text file containing the GNU General Public License version 3. * [AUTHORS][authors-link], a text file with the list of authors for the project. * [src][src-link], a subdirectory containing the full source code, including a Makefile that can be used to compile Stockfish on Unix-like systems. * a file with the .nnue extension, storing the neural network for the NNUE evaluation. Binary distributions will have this file embedded. ## The UCI protocol and available options The Universal Chess Interface (UCI) is a standard protocol used to communicate with a chess engine, and is the recommended way to do so for typical graphical user interfaces (GUI) or chess tools. Stockfish implements the majority of its options as described in [the UCI protocol][uci-link]. Developers can see the default values for UCI options available in Stockfish by typing `./stockfish uci` in a terminal, but the majority of users will typically see them and change them via a chess GUI. This is a list of available UCI options in Stockfish: * #### Threads The number of CPU threads used for searching a position. For best performance, set this equal to the number of CPU cores available. * #### Hash The size of the hash table in MB. It is recommended to set Hash after setting Threads. * #### Clear Hash Clear the hash table. * #### Ponder Let Stockfish ponder its next move while the opponent is thinking. * #### MultiPV Output the N best lines (principal variations, PVs) when searching. Leave at 1 for best performance. * #### Use NNUE Toggle between the NNUE and classical evaluation functions. If set to "true", the network parameters must be available to load from file (see also EvalFile), if they are not embedded in the binary. * #### EvalFile The name of the file of the NNUE evaluation parameters. Depending on the GUI the filename might have to include the full path to the folder/directory that contains the file. Other locations, such as the directory that contains the binary and the working directory, are also searched. * #### UCI_AnalyseMode An option handled by your GUI. * #### UCI_Chess960 An option handled by your GUI. If true, Stockfish will play Chess960. * #### UCI_ShowWDL If enabled, show approximate WDL statistics as part of the engine output. These WDL numbers model expected game outcomes for a given evaluation and game ply for engine self-play at fishtest LTC conditions (60+0.6s per game). * #### UCI_LimitStrength Enable weaker play aiming for an Elo rating as set by UCI_Elo. This option overrides Skill Level. * #### UCI_Elo If enabled by UCI_LimitStrength, aim for an engine strength of the given Elo. This Elo rating has been calibrated at a time control of 60s+0.6s and anchored to CCRL 40/4. * #### Skill Level Lower the Skill Level in order to make Stockfish play weaker (see also UCI_LimitStrength). Internally, MultiPV is enabled, and with a certain probability depending on the Skill Level a weaker move will be played. * #### SyzygyPath Path to the folders/directories storing the Syzygy tablebase files. Multiple directories are to 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 HDD. It is recommended to verify all md5 checksums of the downloaded tablebase files (`md5sum -c checksum.md5`) as corruption will lead to engine crashes. * #### SyzygyProbeDepth Minimum remaining search depth for which a position is probed. Set this option to a higher value to probe less aggressively if you experience too much slowdown (in terms of nps) due to tablebase probing. * #### Syzygy50MoveRule Disable to let fifty-move rule draws detected by Syzygy tablebase probes count as wins or losses. This is useful for ICCF correspondence games. * #### SyzygyProbeLimit Limit Syzygy tablebase probing to positions with at most this many pieces left (including kings and pawns). * #### Move Overhead Assume a time delay of x ms due to network and GUI overheads. This is useful to avoid losses on time in those cases. * #### Slow Mover Lower values will make Stockfish take less time in games, higher values will make it think longer. * #### nodestime Tells the engine to use nodes searched instead of wall time to account for elapsed time. Useful for engine testing. * #### Debug Log File Write all communication to and from the engine into a text file. For developers the following non-standard commands might be of interest, mainly useful for debugging: * #### bench *ttSize threads limit fenFile limitType evalType* Performs a standard benchmark using various options. The signature of a version (standard node count) is obtained using all defaults. `bench` is currently `bench 16 1 13 default depth mixed`. * #### compiler Give information about the compiler and environment used for building a binary. * #### d Display the current position, with ascii art and fen. * #### eval Return the evaluation of the current position. * #### export_net [filename] Exports the currently loaded network to a file. If the currently loaded network is the embedded network and the filename is not specified then the network is saved to the file matching the name of the embedded network, as defined in evaluate.h. If the currently loaded network is not the embedded network (some net set through the UCI setoption) then the filename parameter is required and the network is saved into that file. * #### flip Flips the side to move. ## A note on classical evaluation versus NNUE evaluation Both approaches assign a value to a position that is used in alpha-beta (PVS) search to find the best move. The classical evaluation computes this value as a function of various chess concepts, handcrafted by experts, tested and tuned using fishtest. The NNUE evaluation computes this value with a neural network based on basic inputs (e.g. piece positions only). The network is optimized and trained on the evaluations of millions of positions at moderate search depth. The NNUE evaluation was first intr