+++ /dev/null
-## Overview
-
-[](https://travis-ci.org/official-stockfish/Stockfish)
-[](https://ci.appveyor.com/project/mcostalba/stockfish/branch/master)
-
-[Stockfish](https://stockfishchess.org) is a free, powerful UCI chess engine
-derived from Glaurung 2.1. It is not a complete chess program and requires a
-UCI-compatible 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.
-
-
-## 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 version 3.
-
- * src, a subdirectory containing the full source code, including a Makefile
- that can be used to compile Stockfish on Unix-like systems.
-
-
-## UCI parameters
-
-Currently, Stockfish has the following UCI options:
-
- * #### Debug Log File
- Write all communication to and from the engine into a text file.
-
- * #### Contempt
- A positive value for contempt favors middle game positions and avoids draws.
-
- * #### Analysis Contempt
- By default, contempt is set to prefer the side to move. Set this option to "White"
- or "Black" to analyse with contempt for that side, or "Off" to disable contempt.
-
- * #### 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.
-
- * #### 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.
-
- * #### 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.
-
- * #### 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).
-
- * #### 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.
-
- * #### UCI_Chess960
- An option handled by your GUI. If true, Stockfish will play Chess960.
-
- * #### UCI_AnalyseMode
- An option handled by your GUI.
-
- * #### 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 HD. 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 agressively if you experience too much slowdown
- (in terms of nps) due to TB 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).
-
-
-## What to expect from Syzygybases?
-
-If the engine is searching a position that is not in the tablebases (e.g.
-a position with 8 pieces), it will access the tablebases during the search.
-If the engine reports a very large score (typically 153.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 this 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.
-
-## Large Pages
-
-Stockfish supports large pages on Linux and Windows. Large pages make
-the hash access more efficient, improving the engine speed, especially
-on large hash sizes. Typical increases are 5..10% in terms of nps, but
-speed increases up to 30% have been measured. The support is
-automatic. Stockfish attempts to use large pages when available and
-will fall back to regular memory allocation when this is not the case.
-
-### Support on Linux
-
-Large page support on Linux is obtained by the Linux kernel
-transparent huge pages functionality. Typically, transparent huge pages
-are already enabled and no configuration is needed.
-
-### Support on Windows
-
-The use of large pages requires "Lock Pages in Memory" privilege. See
-[Enable the Lock Pages in Memory Option (Windows)](https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/enable-the-lock-pages-in-memory-option-windows)
-on how to enable this privilege. Logout/login may be needed
-afterwards. Due to memory fragmentation, it may not always be
-possible to allocate large pages even when enabled. A reboot
-might alleviate this problem. To determine whether large pages
-are in use, see the engine log.
-
-## Compiling Stockfish yourself from the sources
-
-Stockfish has support for 32 or 64-bit CPUs, certain hardware
-instructions, big-endian machines such as Power PC, and other platforms.
-
-On Unix-like systems, it should be easy to compile Stockfish
-directly from the source code with the included Makefile in the folder
-`src`. In general it is recommended to run `make help` to see a list of make
-targets with corresponding descriptions.
-
-```
- cd src
- make help
- make build ARCH=x86-64-modern
-```
-
-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.
-
-When reporting an issue or a bug, please tell us which version and
-compiler you used to create your executable. These informations can
-be found by typing the following commands in a console:
-
-```
- ./stockfish
- compiler
-```
-
-## Understanding the code base and participating in the project
-
-Stockfish's improvement over the last couple of years has been a great
-community effort. There are a few ways to help contribute to its growth.
-
-### Donating hardware
-
-Improving Stockfish requires a massive amount of testing. You can donate
-your hardware resources by installing the [Fishtest Worker](https://github.com/glinscott/fishtest/wiki/Running-the-worker:-overview)
-and view the current tests on [Fishtest](https://tests.stockfishchess.org/tests).
-
-### Improving the code
-
-If you want to help improve the code, there are several valuable resources:
-
-* [In this wiki,](https://www.chessprogramming.org) many techniques used in
-Stockfish are explained with a lot of background information.
-
-* [The section on Stockfish](https://www.chessprogramming.org/Stockfish)
-describes many features and techniques used by Stockfish. However, it is
-generic rather than being focused on Stockfish's precise implementation.
-Nevertheless, a helpful resource.
-
-* The latest source can always be found on [GitHub](https://github.com/official-stockfish/Stockfish).
-Discussions about Stockfish take place in the [FishCooking](https://groups.google.com/forum/#!forum/fishcooking)
-group and engine testing is done on [Fishtest](https://tests.stockfishchess.org/tests).
-If you want to help improve Stockfish, please read this [guideline](https://github.com/glinscott/fishtest/wiki/Creating-my-first-test)
-first, where the basics of Stockfish development are explained.
-
-
-## Terms of use
-
-Stockfish is free, and distributed under the **GNU General Public License version 3**
-(GPL v3). 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 v3 found in the file named
-*Copying.txt*.
projects / stockfish / blobdiff