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<span id="MultipleTables"></span>
=Multiple Tables=
Most modern programs, influenced by [[Fruit]], use two sets of tables. One for the [[Opening|opening]] of the game and another for the [[Endgame|endgame]]. The final evaluation is them then [[Tapered Eval|interpolated]] between these two based on [[Game Phases|game stage]] (often [[Material|material]] on the board). This allows for changes in material as well, since the material part of the evaluation can also be stored in these tables. Using two tables also lets pieces change in evaluation as the game proceeds. For example, [[Pawn|pawns]] can gain in value in the endgame using this method.
<span id="Preprocessing"></span>
=Pre-processing=
With today's search depth this approach seems to be impractical, since the difference between the root and leaf position may be very big. There also might be a problem with re-using hash scores from the previous entries. About the only recent chess program that sticks with pre-processing for good or bad is [[RomiChess]] <ref>[https://www.stmintz.com/ccc/index.php?id=18203 Re: What is "pre-processing"] by [[Ulrich Türke]], [[CCC]], May 08, 1998</ref> <ref>[https://www.stmintz.com/ccc/index.php?id=18213 Re: What is "pre-processing"] by [[Amir Ban]], [[CCC]], May 08, 1998</ref>.
=ExampleExamples= Material and piece-square tables alone are enough for a program to play a semi-decent game of chess. Indeed, [[Tomasz Michniewski]] advocated a method of testing requiring all the tested programs to have identical, simplistic evaluation function, so that only search and efficiency issues would influence the result. One such tournament has been carried out in Poland.[[Ronald Friederich]] improved this approach using a [[Tapered Eval]] and [[Texel's Tuning Method|Texel's tuning method]] as applied in [[RofChade]] and [[PeSTO]].
* [[Simplified Evaluation Function]]
* [[PeSTO's Evaluation Function]]
=See also=
* [[Oracle]]
* [[Space]]
* [[Tapered Eval]]
=Publications=
==2010 ...==
* [http://www.talkchess.com/forum/viewtopic.php?t=37191 dynamically modified evaluation function] by [[Don Dailey]], [[CCC]], December 20, 2010
'''2011'''
* [http://www.talkchess.com/forum/viewtopic.php?t=38766 Move ordering by PST] by [[Onno Garms]], [[CCC]], April 16, 2011 » [[History Heuristic]], [[Move Ordering]], [[Onno]]
* [http://www.open-chess.org/viewtopic.php?f=5&t=1535 Questions for BB about Rybka PST = Fruit PST] by [[Ed Schroder|Rebel]], [[Computer Chess Forums|OpenChess Forum]], August 4, 2011 » [[Rybka Controversy]]
* [http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?tid=22669 Take the Fruit Bishop tables...] by [[Miguel A. Ballicora|michiguel]], [[Computer Chess Forums|Rybka Forum]], August 16, 2011
* [http://www.open-chess.org/viewtopic.php?f=5&t=1570 PST of Fruit 2.1 and Rybka 1.0 Beta] by [[Mark Watkins|BB+]], [[Computer Chess Forums|OpenChess Forum]], August 22, 2011
'''2012'''
* [http://www.talkchess.com/forum/viewtopic.php?t=42167 Incremental or non-incremental PST evaluation calcs] by [[Mark Pearce]], [[CCC]], January 26, 2012 » [[Incremental Updates]]
* [http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=475603&t=44507 Re: Some thoughts on QS] by [[Don Dailey]], [[CCC]], July 25, 2012 » [[Quiescence Search]]
'''2013'''
* [http://www.talkchess.com/forum/viewtopic.php?t=48102 On history and piece square tables] by [[Evert Glebbeek]], [[CCC]], May 24, 2013 » [[History Heuristic]]
* [http://www.talkchess.com/forum/viewtopic.php?t=50294 PSQ tables depending on king sides, pawn patterns etc.] by [[Sergei Markoff|Sergei S. Markoff]], [[CCC]], December 01, 2013
'''2014'''
* [http://www.talkchess.com/forum/viewtopic.php?t=50840 Piece/square table challenge] by [[Pawel Koziol]], [[CCC]], January 09, 2014
* [http://www.talkchess.com/forum/viewtopic.php?t=51518 SEE logic] by [[Youri Matiounine]], [[CCC]], March 08, 2014 » [[Static Exchange Evaluation]]
* [http://www.talkchess.com/forum/viewtopic.php?t=57575 high values of pst] by [[Daniel Anulliero]], [[CCC]], September 09, 2015
* [http://www.talkchess.com/forum/viewtopic.php?t=58231 pieces psqt] by [[Alexandru Mosoi]], [[CCC]], November 11, 2015
'''2016'''
* [http://www.talkchess.com/forum/viewtopic.php?t=61631 Sanity check on piece-value tables] by [[Stuart Riffle]], [[CCC]], October 06, 2016
* [http://www.talkchess.com/forum/viewtopic.php?t=62257 Simple method for simple mates for programs without TBs] by [[J. Wesley Cleveland]], [[CCC]], November 25, 2016 » [[KBNK Endgame]], [[Mop-up Evaluation]]
'''2017'''
* [http://www.talkchess.com/forum/viewtopic.php?t=64972 Approximating Stockfish's Evaluation by PSQTs] by [[Thomas Dybdahl Ahle]], [[CCC]], August 23, 2017 » [[Automated Tuning#Regression|Regression]], [[Stockfish]]
'''2018'''
* [http://www.talkchess.com/forum/viewtopic.php?t=66588 Learning piece-square table] by [[Mathieu Pagé]], [[CCC]], February 13, 2018 » [[Automated Tuning]]
* [http://www.talkchess.com/forum/viewtopic.php?t=66966 'ab-initio' piece values] by [[Harm Geert Muller]], [[CCC]], March 30, 2018 » [[Point Value]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=68311&start=19 Re: New uci engine: Rofchade] by [[Ronald Friederich]], [[CCC]], August 28, 2018 » [[RofChade]], [[Tapered Eval]]
==2020 ...==
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=73865 PST for FRC] by [[Vivien Clauzon]], [[CCC]], May 07, 2020 » [[Chess960]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=74752 Using piece-square table score for move ordering] by [[Maksim Korzh]], [[CCC]], August 11, 2020 » [[Move Ordering]]
* [https://prodeo.actieforum.com/t120-engine-choosing-between-sets-of-piece-square-tables Engine choosing between sets of piece/square tables] by [[Pawel Koziol|nescitus]], [[Computer Chess Forums|ProDeo Forum]], December 05, 2020
'''2021'''
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=76256 Piece square tables] by [[Elias Nilsson]], [[CCC]], January 08, 2021
* [https://prodeo.actieforum.com/t252-little-fun-with-tscp little fun with TSCP] by [[Pawel Koziol|nescitus]], [[Computer Chess Forums|ProDeo Forum]], February 12, 2021 » [[TSCP]], [[PeSTO's Evaluation Function]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=76831 The PSTs of Carnivor] by [[Michael Sherwin|Mike Sherwin]], [[CCC]], March 10, 2021
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=77089 PST-only Evaluation for MinimalChess 0.4] by [[Thomas Jahn]], [[CCC]], April 15, 2021 » [[MinimalChess]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=77379 Evaluating piece value] by Jon Lawrance, [[CCC]], May 25, 2021 » [[Point Value]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=77546 Game Phase and tapered PSQT evaluation] by Jon12345, [[CCC]], June 23, 2021 » [[PeSTO's Evaluation Function]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=77667 multi-PST for middle-game depend from kings positions] by [[Eugene Kotlov]], [[CCC]], July 08, 2021
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=77715 Just an untested idea] by [[Ed Schroder|Ed Schröder]], [[CCC]], July 12, 2021 » [[Automated Tuning]]
'''2022'''
* [https://www.talkchess.com/forum3/viewtopic.php?f=7&t=79401 Stuck trying to come up with my own PST values] by Kurt Peters, [[CCC]], February 22, 2022
* [https://www.talkchess.com/forum3/viewtopic.php?f=7&t=79049&start=127 Re: Devlog of Leorik - A.k.a. how to tune high-quality PSTs from scratch (material values) in 20 seconds] by [[Thomas Jahn]], [[CCC]], March 28, 2022 » [[Automated Tuning]], [[Leorik]]
=External Links=
* [http://home.hccnet.nl/h.g.muller/pcsqr.html Evaluation: Piece-Square Tables] from [[Micro-Max]] by [[Harm Geert Muller]]
* Cage. Music, art, chess - Film by Brian Brandt with [https://en.wikipedia.org/wiki/Margaret_Leng_Tan Margaret Leng Tan] and [https://www.linkedin.com/in/larry-list-937b888 Larry List], [https://en.wikipedia.org/wiki/Noguchi_Museum Noguchi Museum] <ref>[https://shop.noguchi.org/imofchre.html The Imagery of Chess Revisited]</ref> <ref>[https://www.youtube.com/watch?v=vegmCb9j4kE Discovering The Imagery of Chess featuring Larry List], 2017, [https://en.wikipedia.org/wiki/YouTube YouTube] Video </ref> <ref>[http://www.edochess.ca/batgirl/Imagery_of_Chess3.html The Imagery of Chess -Surrealism and Chess]</ref>, 2006, [https://en.wikipedia.org/wiki/YouTube YouTube] Video
: {{#evu:https://www.youtube.com/watch?v=Hva8WMcRyOE|alignment=left|valignment=top}}
