A chess engine to learn and play with. Compatible with both xboard/winboard and UCI.
For a year and a half Minic was (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 developped as a week-end project (in mid-october 2018), the quick-and-dirty way, and since then I was having fun going on this way ; being a "small" code size engine was part of the stakes in developing it. Second reason is that it helps the compilers optimize the whole code (at least that is what I though...)
Until version 2 of Minic, some optional features such as Texel tuning, perft, tests, uci support, book generation ... were available in the Add-Ons directory ; they are now fused with the source code.
Indeed, since version "2" Minic is now written in a more classic c++ style, although very dense lines are still present and recall Minic past compacity...
Initially, the code size was supposed not to go above 2000sloc. It started as a week-end project in october 2018 (http://talkchess.com/forum3/viewtopic.php?f=2&t=68701). But, as soon as more features (especially SMP, material tables and bitboard) came up, I tried to keep it under 4000sloc and then 5000sloc. This is why this engine was named Minic, this stands for "Minimal Chess" (and is not related to the GM Dragoljub Minić) but it has not much to do with minimalism anymore...
Version "1" was release as a one year anniversary release in october 2019. At this point Minic has already go from a 1800 Elo 2-days-of-work engine, to a 2800 Elo engine being invited at TCEC qualification league.
Version "2" is release for April 1st 2020 (during covid-19 confinement). For this version, the one file Minic was splitted into many header and source files, and commented a lot more without negative impact on speed and strength.
WARNING : Dist directory as been REMOVED from the repository because it was starting to be too big. Unofficial releases are not available anymore. This operation has changed Minic git history, so you shall probably re-clone a clean repo. All (unofficial) releases are available in a new repo, here : https://github.com/tryingsomestuff/Minic-Dist
Some stable/official ones will also be made available as github release. I "officially release" (create a github version) as soon as I have some validated elo (at least +10).
In a github release, a tester shall only use the given (attached) binaries. The full "source" package always contains everything (source code, test suites, opening suite, books, ...).
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).
Starting from release 1.00 Minic support setting options using protocol (both XBoard and UCI). Option priority are as follow : command line option can be override by protocol option.
Minic 1.39 is tested at 2842 on the CCRL 40/15 scale (http://ccrl.chessdom.com/ccrl/4040/)
Minic 1.35 is tested at 3029 on the CCRL BLITZ 4CPU scale (http://ccrl.chessdom.com/ccrl/404/).
Minic 1.44 is tested at 3015 on the CCRL BLITZ 1CPU scale (http://ccrl.chessdom.com/ccrl/404/).
Minic 1.15 is tested at 2830 on the CCRL FRC list (http://ccrl.chessdom.com/ccrl/404FRC/)
Minic 1.35 is tested at 2836 on the CEGT 40/4 list (http://www.cegt.net/40_4_Ratinglist/40_4_single/rangliste.html)
Minic 1.35 is tested at 3067 on the CEGT 40/4 MP list (http://www.cegt.net/40_4_Ratinglist/40_4_mp/rangliste.html)
Minic 1.35 is tested at 2882 on the CEGT 5+3 PB=ON list (http://www.cegt.net/5Plus3Rating/BestVersionsNEW/rangliste.html)
Minic 1.44 is tested at 2797 on the CEGT 40/15 list (http://www.cegt.net/40_40%20Rating%20List/40_40%20SingleVersion/rangliste.html)
Minic 1.44 is tested at 2740 on the fastgm 60sec+0.6sec rating list (http://www.fastgm.de/60-0.60.html)
Minic 1.51 is tested at 2916 on the fastgm 10min+6sec rating list (http://www.fastgm.de/10min.html)
STS : 1169/1500 @10sec per position (single thread)
WAC : 289/300 @10sec per position (single thread)
Here are some fast TC results (CCRL Blitz TC)
Rank Name Elo +/- Games Score Draws
0 minic_1.49 9 6 7842 51.3% 46.2%
1 RubiChess 185 28 412 74.4% 35.2%
2 demolito 104 27 413 64.5% 36.1%
3 igel-last 76 25 413 60.8% 45.0%
4 PeSTO_bmi2 19 26 413 52.7% 38.5%
5 Winter0.7 5 26 412 50.7% 40.3%
6 minic_1.48 -1 19 412 49.9% 68.7%
7 Hakkapeliitta -5 27 413 49.3% 33.2%
8 amoeba -6 24 413 49.2% 47.0%
9 minic_1.45 -13 20 413 48.2% 64.4%
10 Topple_master -17 26 412 47.6% 39.8%
11 rodentIV -23 26 413 46.7% 39.7%
12 minic_1.46 -24 21 413 46.6% 61.3%
13 cheng4_linux_x64 -30 25 413 45.6% 43.3%
14 minic_1.39 -45 20 413 43.6% 65.4%
15 minic_1.35 -66 22 413 40.7% 55.7%
16 combusken-linux-64 -70 27 413 40.1% 38.0%
17 zurichess-neuchatel -74 26 412 39.6% 39.8%
18 minic_1.19 -76 23 413 39.2% 51.3%
19 FabChessv1.13 -102 28 413 35.7% 34.6%
Minic strength can be ajdusted using the level option (from command line, json configuration file, or using protocol option support, using value from 0 to 100). Level 0 is a random mover, 1 to 30 very weak, ..., level 100 is full strength. Level functionnaly will be enhanced in a near future.
Minic random-mover stats are the following :
7.73% 0-1 {Black mates}
7.50% 1-0 {White mates}
2.45% 1/2-1/2 {Draw by 3-fold repetition}
21.99% 1/2-1/2 {Draw by fifty moves rule}
54.16% 1/2-1/2 {Draw by insufficient mating material}
6.13% 1/2-1/2 {Draw by stalemate}
Current level elo are more or less so that even a kid can beat low levels Minic. From level 50 or 60, you will start to struggle more !
- 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.
To compile with SYZYGY support you'll need to clone https://github.com/jdart1/Fathom as Fathom directory and activate WITH_SYZYGY definition at compile time. To use EGT just specify syzygyPath in the configuration file or in the command line.
add the command line option "-xboard" to go to xboard/winboard mode or -uci for UCI.
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
- -qsearch <"fen"> : just a qsearch ...
- -mateFinder <"fen"> depth : same as analysis but without prunings in search
- -pgn : extraction tool to build tuning data
- -texel : run a texel tuning session
- ...
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.bin",
"fullXboardOutput": true,
"debugMode": false,
"debugFile": "minic.debug",
"level": 100,
"syzygyPath": "/data/minic/TB/syzygy"
}
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.
Starting from release 1.00, important options are also available through protocol.
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)
- 0.75 : backward pawn, tweak SEE
- 0.76 : refactoring eval scoring
- 0.77 : better use of bitboard in pawn eval
- 0.78 : candidate
- 0.79 : bug fix in SEE, pondering and analysis mode
- 0.80 : level from 0 to 10. 0 is random mover, 10 is full strength
- 0.81 : working on random mover and pondering
- 0.82 : finally a working pondering release ...
- 0.83 : bug fix, pawn PST were not use anymore ... :-S
- 0.84 : little search and eval tweaking
- 0.85 : window search bug fix
- 0.86..0.87 : working on search and move ordering
- 0.88..0.91 : add and fix some eval features, try queen/king proximity, try BM extension
- 0.92 : fix extension/reduction
- 0.93..0.95 : re-tune almost everything
- 0.96..0.98 : some tuning and SEE fix
- 0.99 : random draw eval
- 1.00 : tweak eval and search, work on TT scheme, some fixes, !!! 1 year anniversary release !!!
- 1.01..1.09 : work on dedicated pawn table for eval, many eval fixes, search tweaks
- 1.10..1.14 : work on move ordering
- 1.15 : FRC !
- 1.16..1.19 : work on killer, history and counter
- 1.19..1.26 : mainly TCEC QL preparation and debugging
- 1.26..1.34 : mainly TCEC L2 preparation, debugging and cleaning
- 1.35..1.38 : playing with SEE, initiative, imbalance, danger, ...
- 1.39..1.40 : tuning search SEE and LMR with danger score from evaluation
- 1.41..1.42 : fixing a time management issue with incremental TC
- 1.43 : qsearch cleaning
- 1.44 : bad bishop eval
- 1.45..1.50 : search tuning / trick, simpler hash table.
- 1.51 : retune everything !
- 1.52..1.54 : retune queen near king, PST and mobility
- 1.55 : multi PV
- 2.00 : splitting the one file Minic into many header / source files
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, Season 16 qualification league and Season 17 QL and L1, 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)