Engine Testing

**[[Home]] * Engine Testing**
|| [[image:coyote.jpg link="http://sanseverything.wordpress.com/2008/01/16/hope-springs-eternal/"]] ||~   || **Engine Testing**,
the process either to eliminate [[https://en.wikipedia.org/wiki/Software_bug|bugs]] and to measure [[Playing Strength|performance]] of a chess engine. New implementations of [[Move Generation|move generation]] are tested with [[Perft]], while new features and [[Automated Tuning|tuning]] of [[Search|search]] and [[Evaluation|evaluation]] are verified by [[Test-Positions|test-positions]] and by playing [[Match Statistics|matches]] against other engines. ||
|| The ever-optimistic [[https://en.wikipedia.org/wiki/Wile_E._Coyote_and_Road_Runner|Wile E. Coyote]] <ref>[[http://sanseverything.wordpress.com/2008/01/16/hope-springs-eternal/|Hope Springs Eternal]]</ref> ||~   ||^   ||
[[toc]]
=Bug Hunting= 
* [[Perft]] ([[Perft Results]])
* [[Debugging]]

=Analyzing=
* [[Logging]]
* [[Profiling]]
* [[Search Statistics]]

=Tuning= 
* [[Automated Tuning]]

=Test-Positions= 
Running sets of test-positions with number of solutions per fixed time-frame is useful to prove whether things are broken after program changes or to get hints about missing knowledge. But one should be careful to tune engines based on test-position results, since solving (possible tactical) test-positions does not necessarily correlate with practical [[Playing Strength|playing strength]] in matches against other opponents.
* [[Test-Positions]]
[[#Matches]]
=Matches= 
Most testing involves running different versions of a program in matches, and comparing results.

==Time Controls== 
Generally speaking, for testing changes that don't alter the search tree itself, but only affect performance (eg. [[Move Generation|move generation]]) can be tested with given fixed nodes, fixed time or fixed depth. In all other cases the [[Time Management|time management]] should be left to the engine to simulate real tournament conditions. On the other hand, [[Debugging|debugging]] is much easier under fixed conditions as the games become deterministic.

A side from the type of [[Time Management#Time%20Controls|time control]] one also has to decide on how much time should be spent per game, ie. what the average quality of the games should be like. While one can test more changes in the a certain time at short time controls, it is also relevant how a certain change scales to different strengths. So for example should one increase the [[Depth Reduction R|R]] in [[Null Move Pruning|Null move pruning]] to 3 in depths > 7, this change may only be effectively tested on time controls where this new condition is triggered frequently enough, ie. where the average search depth is far greater than seven. It is hard to generalize, but on average changes of the search functions ([[Late Move Reductions|LMR]], [[Null Move|nullmove]], [[Futility Pruning|futility]] or similar [[Pruning|pruning]], [[Reductions|reductions]] and [[Extensions|extensions]] ) tend to be more sensitive to the time control than the tuning of [[Evaluation|evaluation]] parameters.

==Opening== 
During testing the engines should ideally play the same style of openings they would play in a normal tournament, so not to optimize them for different types of positions. One option is to use the engines own [[Opening Book|opening book]] or one can use [[Test-Positions#OpeningSuites|opening suites]], a set of quiet test positions. In the latter case the same opening suit would be used for each tournament conducted and furthermore each position is played a second time with colors reversed. With these measures one can try to minimize the disparity between tests caused by different openings.

==Interfaces== 
Free [[GUI|graphical user interfaces]] or [[CLI|command line tools]] for [[UCI]] and [[Chess Engine Communication Protocol]] compatible engines in engine-engine matches are:
* [[Amoeba#TournamentManager|Amoeba Tournament Manager]]
* [[Arena]] by [[Martin Blume]] <ref>[[http://www.playwitharena.com/|Free chess graphical user interface (GUI) Arena for chess engines]]</ref>
* [[Cute Chess]] by [[Arto Jonsson]] and [[Ilari Pihlajisto]]
> [[Cutechess-cli]]
* [[LittleBlitzer]] by [[Nathan Thom]] <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=35249|Fast Games]] by [[Manuel Diaz]], [[CCC]], July 02, 2010</ref>

==Frameworks==
* [[Stockfish#TestingFramework|Fishtest]]
[[#ChessServer]]
==Chess Server== 
One can also test an engine's performance by comparing it to other programs on the various internet platforms <ref>[[http://en.wikipedia.org/wiki/Category:Internet_chess_servers|Internet chess servers from Wikipedia]]</ref> . In this case the different hardware and features like different [[Endgame Tablebases]] or [[Opening Book|Opening Books]] have to be considered.
* [[Chess Server]]
* [[Tournaments]]

==Statistics== 
The question whether certain results actually indicates a [[Playing Strength|strength]] increase or not, can be answered with 
* [[Match Statistics]]
* [[Pawn Advantage, Win Percentage, and Elo]]
* [[LOS Table]]
[[#Ratings]]
==Ratings==
* [[Rating System]]
* [[Engine Rating Lists]]
[[#TestResults]]
=Test Results= 
* [[Null Move Pruning Test Results]]
* [[Late Move Reduction Test Results]]
[[#bugs]]
=Notable Bugs= 
* [[Brute Force (Program)]], [[En passant#bugs|En passant bug]], [[ACM 1977]] and [[ACM 1978]]
* [[Coko#MateBug|Coko - Mate in One?]], [[ACM 1971]]
* [[4th Computer Olympiad#PromotionBug|Chess 2175X vs. Genesis]], [[Promotions|Promotion]] bug, [[4th Computer Olympiad#Chess|4th Computer Olympiad 1992]]
* [[WMCCC 1993#NimzoBug|Nimzo's winning white-black bug]], [[WMCCC 1993]]
* [[Novag Micro Chess#CastlingBug|Novag Micro Chess - Castling bug]], [[CPWTIPC 1981]]
* [[Proscha#bugs|Proscha]] capturing its own king versus [[Daja]], [[First GI Computer Chess Tournament|First GI Computer Chess Tournament 1975]]
* [[WMCCC 1995#TalXXXX|System Tal vs. XXXX]], [[Promotions|Promotion]] bug, [[WMCCC 1995]]
* [[XiniX|Xinix - Mate in One]], [[DOCCC 2000]] <ref>[[http://www.xs4all.nl/~timkr/chess2/honor.htm|Defending Humanity's Honor]] by [[http://en.wikipedia.org/wiki/Tim_Krabb%C3%A9|Tim Krabbé]]</ref>

=Publications= 
* [[Tony Marsland]], [[Paul Rushton]] (**1973**). //[[http://dl.acm.org/citation.cfm?id=805703|Mechanisms for Comparing Chess Programs]].// [[ACM 1973|ACM Annual Conference]], [[http://webdocs.cs.ualberta.ca/~tony/OldPapers/Marsland-Rushton-ACM73|pdf]]
* [[Tim Breitkreutz]], [[Jonathan Schaeffer]] (**1984**). //Computer vs Computer via Computer//. [[ICGA Journal#7_4|ICCA Journal, Vol. 7, No. 4]]
* [[John Stanback]] (**1990**). //Supercomputing '90: Computer-Chess Testing and Programming Session//. [[ICGA Journal#13_4|ICCA Journal, Vol. 13, No. 4]] » [[ACM 1990]]
* [[Larry Kaufman]] (**1993**). //How Our PC Chess Programs Are Developed//. [[Computer Chess Reports]] 1992-93, Vol. 3, No. 2, pp. 12
* [[Thomas Mally]] (**1993**). //Matt in Wieviel?// [[PC Schach]] 3/93 (German)
* [[Jeff Rollason]] (**2007**). //[[http://www.aifactory.co.uk/newsletter/2007_04_stat_minefields.htm|Statistical Minefields with Version Testing]]//. [[AI Factory]], Winter 2007 » [[Match Statistics]]
* [[Jónheiður Ísleifsdóttir]] (**2007**). //GTQL: A Query Language for Game Trees//. M.Sc. thesis, [[http://en.wikipedia.org/wiki/Reykjav%C3%ADk_University|Reykjavík University]], [[http://www.ru.is/lisalib/getfile.aspx?itemid=9655|pdf]]
* [[Jónheiður Ísleifsdóttir]], [[Yngvi Björnsson]]. (**2008**). //[[http://link.springer.com/chapter/10.1007/978-3-540-87608-3_20|GTQ: A Language and Tool for Game-Tree Analysis]]//. [[CG 2008]], [[http://www.ru.is/faculty/yngvi/pdf/IsleifsdottirB08.pdf|pdf]]

=Forum Posts=
==1995 ...==
* [[http://groups.google.com/group/rec.games.chess.computer/browse_frm/thread/2aaa054105f1445e|Testing Chess Programs]] by [[Jan Eric Larsson]], [[Computer Chess Forums|rgcc]], February 09, 1996
* [[http://www.stmintz.com/ccc/index.php?id=13569|Self-test and others rating stuffs...]] by [[Christophe Théron]], [[CCC]], January 01, 1998
* [[http://www.stmintz.com/ccc/index.php?id=16851|Proposal: New testing methods for SSDF (1)]] by [[Jeroen Noomen]], [[CCC]], April 13, 1998
==2000 ...==
* [[http://www.stmintz.com/ccc/index.php?id=176716|Using 2 machines for matches (Linux)]] by [[Jon Dart]], [[CCC]], June 24, 2001 » [[XBoard]], [[Linux]]
* [[http://www.stmintz.com/ccc/index.php?id=189308|A proposed WAC replacement for testing]] by [[Gian-Carlo Pascutto]], [[CCC]], September 18, 2001 » [[Win at Chess]]
* [[http://www.stmintz.com/ccc/index.php?id=275347|Value of playing different versions of a program against each other]] by [[Tom King]], [[CCC]], January 06, 2003
* [[http://www.stmintz.com/ccc/index.php?id=293815|testing of evaluation function]] by Steven Chu, [[CCC]], April 17, 2003 » [[Evaluation]]
* [[http://www.stmintz.com/ccc/index.php?id=296689|Testing the reliability of forward pruning]] by [[Russell Reagan]], [[CCC]], May 15, 2003 » [[Pruning]]
* [[http://www.stmintz.com/ccc/index.php?id=334370|To programmers: Hints for testing after a partial rewrite]] by [[Federico Andrés Corigliano|Federico Corigliano]], [[CCC]], December 08, 2003
* [[http://www.stmintz.com/ccc/index.php?id=400589|Is there a way?]] by [[Ed Schroder|Ed Schröder]], [[CCC]], December 13, 2004
==2005 ...==
* [[http://www.stmintz.com/ccc/index.php?id=484357|table for detecting significant difference between two engines]] by Joseph Ciarrochi, [[CCC]], February 03, 2006
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=4&t=5866|test methodology]] by [[Giuseppe Cannella]], [[Computer Chess Forums|Winboard Forum]], November 13, 2006
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=4&t=5955|Testing and debugging chess engines]] by [[Patrice Duhamel]], [[Computer Chess Forums|Winboard Forum]], December 03, 2006
* [[http://www.talkchess.com/forum/viewtopic.php?t=13557|Programmer bug hunt challenge]] by [[Ed Schroder|Ed Schröder]], [[CCC]], May 04, 2007 » [[Portable Game Notation]], [[En passant]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=13800|a beat b,b beat c,c beat a question]] by [[Uri Blass]], [[CCC]], May 16, 2007 » [[Playing Strength]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=16412|An objective test process for the rest of us?]] by [[Nicolai Czempin]], [[CCC]], September 12, 2007
* [[http://www.talkchess.com/forum/viewtopic.php?t=17947|My new testing scheme]] by [[Zach Wegner]], [[CCC]], November 20, 2007
* [[http://www.talkchess.com/forum/viewtopic.php?t=22832|New testing thread]] by [[Robert Hyatt]], [[CCC]], August 07, 2008
* [[http://www.talkchess.com/forum/viewtopic.php?t=27024|Cutechess-cli: A command line tool for engine-engine matches]], by [[Ilari Pihlajisto]], [[CCC]], March 16, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=293506&t=27024|Cutechess-cli version 0.1.8 released]] by [[Ilari Pihlajisto]], [[CCC]], September 29, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?t=30513| A reason for testing at fixed number of nodes]] by [[J. Wesley Cleveland]], [[CCC]], November 06, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?t=30550|different kinds of testing]] by [[Don Dailey]], [[CCC]], November 09, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?t=30565|more on fixed nodes]] by [[Robert Hyatt]], [[CCC]], November 10, 2009
==2010 ...==
* [[http://www.talkchess.com/forum/viewtopic.php?t=32254|XBoard and epd tournament]] by [[Vlad Stamate]], [[CCC]], January 31, 2010 » [[Chess Engine Communication Protocol]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=33685|Long game vs short game testing]] by [[Vlad Stamate]], [[CCC]], April 08, 2010
* [[http://www.talkchess.com/forum/viewtopic.php?t=35537|Pairings generation based on a big PGN file]] by [[Harun Taner]], [[CCC]], July 22, 2010
* [[http://www.talkchess.com/forum/viewtopic.php?p=358600|hiatus good for bug-finding]] by [[Stuart Cracraft]], [[CCC]], June 27, 2010
**2011**
* [[http://www.talkchess.com/forum/viewtopic.php?t=39255|testing question]] by [[Larry Kaufman]], [[CCC]], June 01, 2011
* [[http://www.talkchess.com/forum/viewtopic.php?t=39390|Debugging regression tests]] by [[Onno Garms]], [[CCC]], June 16, 2011 <ref>[[http://en.wikipedia.org/wiki/Regression_testing|Regression testing from Wikipedia]]</ref>
**2012**
* [[http://www.talkchess.com/forum/viewtopic.php?t=41876|fast game testing]] by [[Jon Dart]], [[CCC]], January 08, 2012
* [[http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=477389&t=44706&sid=8b10031146b44f86ac4c4a129debf451|Your best bug ?]] by [[Ed Schroder|Ed Schröder]], [[CCC]], August 06, 2012
* [[http://www.talkchess.com/forum/viewtopic.php?t=45158|Yet Another Testing Question]] by [[Brian Richardson]], [[CCC]], September 15, 2012
* [[http://www.talkchess.com/forum/viewtopic.php?t=45287|Another testing question]] by [[Larry Kaufman]], [[CCC]], September 23, 2012
* [[http://www.talkchess.com/forum/viewtopic.php?t=46572|A word for casual testers]] by [[Don Dailey]], [[CCC]], December 25, 2012
**2013**
* [[http://www.talkchess.com/forum/viewtopic.php?t=46759|A poor man's testing environment]] by [[Ed Schroder|Ed Schröder]], [[CCC]], January 04, 2013 <ref>[[http://www.top-5000.nl/tuning.htm|Testing a chess engine from the ground up]] from [[http://www.top-5000.nl/|Home of the Dutch Rebel]] by [[Ed Schroder|Ed Schröder]]</ref> » [[Match Statistics]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=46948|engine-engine testing isues]] by [[Jens Bæk Nielsen]], [[CCC]], January 20, 2013
* [[http://www.talkchess.com/forum/viewtopic.php?t=47407|Beta for Stockfish distributed testing]] by [[Gary Linscott|Gary]], [[CCC]], March 05, 2013 » [[Stockfish#TestingFramework|Fishtest]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=47885|Fishtest Distributed Testing Framework]] by [[Marco Costalba]], [[CCC]], May 01, 2013  » [[Stockfish#TestingFramework|Fishtest]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=48626|cutechess-cli 0.6.0 released]] by [[Ilari Pihlajisto]], [[CCC]], July 12, 2013
* [[http://www.talkchess.com/forum/viewtopic.php?t=49054|fast testing NIT algorithm]] by [[Don Dailey]], [[CCC]], August 22, 2013
* [[http://www.talkchess.com/forum/viewtopic.php?t=49103|OICS: Computers Only ICS based Chess server for anyone]] by [[Joshua Shriver]], [[CCC]], August 26, 2013 » [[OICS]]
**2014**
* [[http://www.talkchess.com/forum/viewtopic.php?t=51383|testing procedure]] by [[Daniel José Queraltó]], [[CCC]], February 23, 2014
==2015 ...==
* [[http://www.talkchess.com/forum/viewtopic.php?t=57437|Bullet vs regular time control, say 40/4m CCRL/CEGT]] by [[Ed Schroder|Ed Schröder]], [[CCC]], August 29, 2015
* [[http://www.talkchess.com/forum/viewtopic.php?t=58359|Static evaluation test posistions]] by [[Shawn Chidester]], [[CCC]], November 25, 2015
> [[http://www.talkchess.com/forum/viewtopic.php?t=58359&start=2|Re: Static evaluation test posistions]] by [[Ferdinand Mosca]], [[CCC]], November 26, 2015 » [[Python]]
**2016**
* [[http://www.talkchess.com/forum/viewtopic.php?t=59038|Ordo 1.0.9 (new features for testers)]] by [[Miguel A. Ballicora]], [[CCC]], January 25, 2016
* [[http://www.talkchess.com/forum/viewtopic.php?t=59984|cluster versus single server]] by [[Folkert van Heusden]], [[CCC]], April 28, 2016
* [[http://www.talkchess.com/forum/viewtopic.php?t=61422|Testing using many computers and architectures]] by [[Andrew Grant]], [[CCC]], September 14, 2016
* [[http://www.talkchess.com/forum/viewtopic.php?t=61988|command line engine match?]] by [[Erin Dame]], [[CCC]], November 06, 2016 » [[CLI]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=62576|Testing with different EPD suits for search vs eval changes]] by [[Michael Sherwin]], [[CCC]], December 23, 2016 
**2017**
* [[http://www.talkchess.com/forum/viewtopic.php?t=62922|sprt tourney manager]] by [[Richard Delorme]], [[CCC]], January 24, 2017 »  [[Amoeba#TournamentManager|Amoeba Tournament Manager]], [[Match Statistics#SPRT|SPRT]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=63001|how to properly test the changes to the engine ?]] by [[Mahmoud Uthman]], [[CCC]], February 01, 2017
* [[http://www.talkchess.com/forum/viewtopic.php?t=63119|How to go about chasing a bug like this?]] by [[Colin Jenkins]], [[CCC]], February 09, 2017 » [[Debugging]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=63454|How to find SMP bugs ?]] by Lucas Braesch, [[CCC]], March 15, 2017 »  [[Debugging]], [[Lazy SMP]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=63555|Testing for Move Ordering Improvements]] by [[Cheney Nattress]], [[CCC]], March 25, 2017 » [[Move Ordering]], [[Search Statistics]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=64356|Testing endgame strength]] by [[Álvaro Begué]], [[CCC]], June 21, 2017 » [[Endgame]], [[RuyDos]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=64358|Opening testing suites efficiency]] by [[Kai Laskos]], [[CCC]], June 21, 2017 » [[Opening]], [[Match Statistics]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=64394|Testing A against B by playing a pool of others]] by [[Andrew Grant]], [[CCC]], June 24, 2017 » [[Match Statistics]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=64441|Core behaviour]] by [[Ed Schroder]], [[CCC]], June 28, 2017 » [[Process]], [[Thread]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=64519|Engine testing & error margin ?]] by [[Mahmoud Uthman]], [[CCC]], July 05, 2017
* [[http://www.talkchess.com/forum/viewtopic.php?t=65766|Engines for testing (Linux, fast time control)]] by [[Jon Dart]], [[CCC]], November 18, 2017 » [[Linux]]

=External Links=
* [[http://ajonsson.kapsi.fi/cutechess.html|Cute Chess]]
* [[https://github.com/cutechess/cutechess|cutechess · GitHub]]
* [[http://www.top-5000.nl/tuning.htm|Testing a chess engine from the ground up]] from [[http://www.top-5000.nl/|Home of the Dutch Rebel]] by [[Ed Schroder|Ed Schröder]] <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=46759|A poor man's testing environment]] by [[Ed Schroder|Ed Schröder]], [[CCC]], January 04, 2013</ref>  » [[Match Statistics]]
* [[https://en.wikipedia.org/wiki/Regression_testing|Regression testing from Wikipedia]]
* [[http://www.sp-cc.de/index.htm|SPCC]] by [[Stefan Pohl]]
* [[http://research.microsoft.com/en-us/projects/chess/|CHESS - Microsoft Research]] a tool for finding and reproducing [[http://en.wikipedia.org/wiki/Unusual_software_bug|Heisenbugs]] in concurrent programs.
* [[https://en.wikipedia.org/wiki/Engine_test_stand|Engine test stand from Wikipedia]]
* [[Videos#TerjeRypdal|Terje Rypdal Group]] feat. [[Videos#PalleMikkelborg|Palle Mikkelborg]], [[https://de.wikipedia.org/wiki/Haakon_Graf|Håkon Graf]], [[http://no.wikipedia.org/wiki/Sveinung_Hovensj%C3%B8|Sveinung Hovensjø]] and [[Videos#JonChristensen|Jon Christensen]] -  [[http://no.wikipedia.org/wiki/Per_Ulv|Per Ulv]], 1978, [[https://en.wikipedia.org/wiki/YouTube|YouTube]] Video
> [[media type="custom" key="23664954"]]

=References= 
<references />
=What links here?= 
[[include component="backlinks" page="Engine Testing" limit="100"]]
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