A simple chess engine to learn and play with. Compatible with xboard/winboard. Initially, the code size was supposed not go above 2000sloc. Now that more features (especially SMP and bitboard) has come up, I'll try to keep it under 3000sloc. This is why Minic stands for "Minimal Chess" (and is not related to the GM Dragoljub Minić).
Minic is (mainly) a one-file-code with very dense lines. This is of course very wrong in terms of software design... So why is it so? First reason is that Minic was first develop as a week-end project, the quick-and-dirty way, and since then I'm having fun going on this way ; being a "small" code size engine is part of the stakes in developing it. Second reason is that it helps the compilers optimize the whole code. The only dependency is the very good json header-only library nlohmann/json used to parse the config file. Some optional features such as Texel tuning, perft, tests, uci support, book generation ... are available in the Add-Ons directory.
Have a look in the Dist directory for releases. Some more stable/official ones will also be made available as github release.
I "release" (create a version number) as soon as I wanna test something. This is usefull for the development process, so that I don't become confused after too much tries... and can revert things properly.
I "officially release" (create a github version) as sson as I have some validated elo (at least +10). Those are version usefull for testers or users.
In a github release, a tester shall only use the given (attached) binaries. The full "source" package always contains everything (source code, all previous versions, test suites, opening suite, books, ...). If you want to use Minic parameter file (minic.json) or some given book file, there are not attached in all release, there are downloadable from the github repo.
Starting from release 0.50 new binaries are available :
* minic_0.50_linux_x64_avx2_bmi2 : fully optimized Linux64 (avx2+bmi2)
* minic_0.50_linux_x64_sse4.2 : optimized Linux64 (sse4.2)
* minic_0.50_linux_x64_x86-64 : basic Linux64
* minic_0.50_mingw_x32_avx2_bmi2.exe: fully optimized Windows32 (avx2+bmi2)
* minic_0.50_mingw_x32_sse4.2.exe : optimized Windows32 (sse4.2)
* minic_0.50_mingw_x32_i686.exe : basic Windows32
* minic_0.50_mingw_x64_avx2_bmi2.exe: fully optimized Windows64 (avx2+bmi2)
* minic_0.50_mingw_x64_sse4.2.exe : optimized Windows64 (sse4.2)
* minic_0.50_mingw_x64_x86-64.exe : basic Windows64
Please note that Win32 binaries are very slow (I don't know why yet, so please use Win64 one if possible).
Minic 0.47 is 2650 on the CCRL 40/40 scale, so way to strong for me ! This is more or less like GM level for human being.
Rank Name Elo +/- Games Score Draws
1 zurichess-neuchatel 235 16 1884 79.4% 20.9%
2 MinkoChess_1.3 200 16 1884 75.9% 19.7%
3 ruy-1.1.9 83 14 1884 61.8% 23.6%
4 minic_0.73 67 13 1884 59.5% 33.5%
5 minic_0.70 58 13 1886 58.2% 34.8%
6 minic_0.72 51 13 1885 57.3% 32.8%
7 minic_0.71 38 13 1885 55.4% 33.6%
8 minic_0.69 20 13 1885 52.9% 32.6%
9 minic_0.65 -9 13 1885 48.6% 33.0%
10 minic_0.61 -16 13 1884 47.7% 31.4%
11 redqueen-1.1.98 -31 14 1884 45.6% 21.9%
12 wyldchess1.51 -32 14 1884 45.5% 25.6%
13 minic_0.53 -44 13 1883 43.7% 31.9%
14 minic_0.57 -51 13 1885 42.7% 29.9%
15 minic_0.47 -71 14 1885 39.9% 25.6%
16 igel -92 14 1883 37.0% 21.3%
17 Fridolin310 -117 15 1884 33.8% 19.5%
18 GreKo -117 15 1885 33.8% 19.7%
19 asymptote-v0.4.2 -138 15 1885 31.1% 17.0%
17902 of 171000 games finished.
- Linux : use the given build script (or make your own ...)
- Windows : use the given VS2017 project (or make your own ...), or use the Linux cross-compilation script given.
add the command line option "-xboard" to go to xboard/winboard mode.
Other available options are :
- -perft_test : run the inner perft test
- -eval <"fen"> : static evaluation of the given position
- -gen <"fen"> : move generation on the given position
- -perft <"fen"> depth : perft on the given position and depth
- -analyze <"fen"> depth : analysis on the given position and depth
- -mateFinder <"fen"> depth : same as analysis but without prunings in search
- ...
Minic now comes with both a json configuration file where some parameters can be set
{
"threads": 1,
"mateFinder": false,
"ttSizeMb": 1024,
"book": true,
"bookFile": "book_big.bin",
"fullXboardOutput": false
}
and a command line interface, using the same key word. For instance, forcing mateFinder mode can be done by adding "-mateFinder 1" when calling Minic.
Minic comes with some opening books written in an internal own binary format. There are currently 4 books
book_small : a very small book only with main variation of classic opening lines
book_big : a bigger book (take 5 secondes to load) of nearly 400.000 lines
Carlsen : based on Carlsen most used opening lines (thanks to Jonathan Cremers)
Anand : based on Anand most used opening lines (thanks to Jonathan Cremers)
You can use both the json configuation file or the command line argument to select the book.
- 0.1 : first commit with the initial code done in less than 2 days
- 0.2-0.5 : many bug fix
- 0.6 : IID
- 0.7 : try TT move first hoping for cut-off
- 0.8 : SEE and LMP
- 0.9 : little internal book
- 0.10 : singular extension for TT move
- 0.11 : on the road to bitboard (only attack), use of "Dumb" HQBB code.
- 0.12 : better use of bitboard, in generation and eval also
- 0.13 : some draw issue fix
- 0.14 : better lmp (use of "improving bool")
- 0.15 : keep track of material count directly in position
- 0.16 : use bitboard for pawn move generation also
- 0.17 : Minic goes SMP !
- 0.18 : configuration file (json) and threads management
- 0.19 : option from command line and fix a TT issue
- 0.20 : clean up code, especially draw management
- 0.21 : add a little more evaluation (basic material bonus/malus)
- 0.22 : not much ...
- 0.23 : try to texel tune pieces value, not sure it is a success
- 0.24 : passer eval
- 0.25 : more aggressive pruning
- 0.26 : fix a TC bug
- 0.27 : smaller window, better singular extension
- 0.28 : xboard time command is used now
- 0.29 : refactoring, very bad TT bug fix, better timeman, better gamephase, work on SEE ... huuuuuge progress. Also preparing for a better eval (pawn structure)...
- 0.30 : add a simple mobility term inside evaluation
- 0.31 : not much
- 0.32 : fix bug in eval
- 0.33 : more aggressive SEE, better move sorting, better time control. Preparing for Syzygy endgame table and end-game helpers KQK, KRK and KBNK.
- 0.34 : just another TC management improvement
- 0.35 : work on material draw
- 0.36 : little optimisations
- 0.37 : MoveList optimisations, fuse eval and score TT, refactoring a lot, bug fixes
- 0.38 : build a bigger book (not used yet), implement the so called easy-move
- 0.39 : fix a bad mate score TT issue, speed up pawn move generation
- 0.40 : pruning in endgame also
- 0.41 : try PSO texel tuning, prepare some evaluation feature, little speed optim
- 0.42 : fix a SMP issue (lock)
- 0.43 : fix another SMP issue
- 0.44 : fix null move that was in fact NOT activated ! activate probcut. Add some counters. New release are sse4.2 and avx2 for both windows and linux.
- 0.45 : lot of clean up in code, search tuning, starts UCI implementation, and fix null move ...
- 0.46 : little optim
- 0.47 : clean up, try uci support
- 0.48 : some evaluation features about Pawn
- 0.49 : more pawn features
- 0.50 : more rook and pawn features (new Win32 releases)
- 0.51 : use bishop pair bonus
- 0.52 : fix history, check extension, some endgames (prepare for pawn hash table ...)
- 0.53 : fix pawn eval
- 0.54 : working on extension and eval
- 0.55 : working on extension and eval
- 0.56 : TC issue in multi-thread mode
- 0.57 : fix 0.56
- 0.58 and 0.59 : trying so add evaluation feature (without success ...)
- 0.60 : use hash in qsearch
- 0.61 : KPK and code clean up
- 0.62 : fix an issue with material when castling, a lot of code refactoring
- 0.63 : others fix
- 0.64 : others fix again, lot of refactoring
- 0.65 : working on search
- 0.66 : working on search again
- 0.67 : working on search again (quiet move SEE)
- 0.68 : working on search again (LMR when in check)
- 0.69..0.74 : tuning eval (texel tuning on Zurichess quiet.edp)
Of course many/most idea in Minic are taken from the beautifull chess developer community. Here's an incomplete list of inspiring open-source engines :
Arasan by Jon Dart
CPW by Pawel Koziol and Edmund Moshammer
Deepov by Romain Goussault
Dorpsgek by Dan Ravensloft
Ethereal by Andrew Grant
Galjoen by Werner Taelemans
Madchess by Erik Madsen
Rodent III by Pawel Koziol
Stockfish by Tord Romstad, Marco Costalba, Joona Kiiski and Gary Linscott
Texel by Peter Österlund
Topple by Vincent Konsolas
TSCP by Tom Kerrigan
Vajolet by Marco Belli
Vice by BlueFeverSoft
Xiphos by Milos Tatarevic
Zurichess by Alexandru Moșoi
Many thanks also to all testers for all those long time control tests, they really are valuable inputs in the chess engine development process.
Also thanks to TCEC for letting Minic participate to the Season 15 division 4a, it was fun to see Minic on such a great hardware.
And of course thanks to all the members of the talkchess forum and CPW, and to H.G. Muller for hosting the friendly monthly tourney.
- Am I a chess player ?
- yes
- good one ?
- no (https://lichess.org/@/xr_a_y)