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Created page with "'''Home * Evaluation * Lazy Evaluation''' FILE:Naturgeschichte und Abbildungen der Reptilien (6059239621).jpg|border|right|thumb|[https://en.wikipedia.org..."
'''[[Main Page|Home]] * [[Evaluation]] * Lazy Evaluation'''
[[FILE:Naturgeschichte und Abbildungen der Reptilien (6059239621).jpg|border|right|thumb|[https://en.wikipedia.org/wiki/Chameleon Chameleons] <ref> [https://en.wikipedia.org/wiki/Chameleon Chameleons], [https://commons.wikimedia.org/wiki/File:Naturgeschichte_und_Abbildungen_der_Reptilien_(6059239621).jpg Plate 99] from [https://en.wikipedia.org/wiki/Heinrich_Rudolf_Schinz Heinrich Rudolf Schinz] ('''1833'''). ''Naturgeschichte und Abbildungen der Reptilien''. lithograph by [https://en.wikipedia.org/wiki/Karl_Joseph_Brodtmann Karl Joseph Brodtmann], [https://en.wikipedia.org/wiki/Wikimedia_Commons Wikimedia Commons]</ref> ]]
In the chess programming sense of the phrase <ref>In general computer programming, [https://en.wikipedia.org/wiki/Lazy_evaluation Lazy evaluation] refers a technique of delaying a computation until the result is required.</ref>, '''Lazy Evaluation''' means dividing all the tasks performed by [[Evaluation function|evaluation function]] in (usually two) stages. If after performing all the tasks for a given stage score exceeds [[Beta|beta]] by a certain margin or if it falls below [[Alpha|alpha]] by the same margin, the score is returned and no more evaluation is conducted. The first stage usually consists of the evaluation terms that are relatively cheap, possibly [[Incremental Updates|incrementally updated]], like [[Material|material]] and [[Piece-Square Tables|piece-square tables]]. Lazy evaluation may be viewed as taking the [[Alpha-Beta|alpha-beta]] principle one step further. If some parts of the evaluation function are omitted due to this heuristics, it means that one side is already winning "the evaluation game" by the margin unacceptable to the opponent, and therefore a cutoff occurs.
=See also=
* [[CPW-Engine_eval]]
* [[Rookie#Evaluation|Evaluation in Rookie 2.0]]
* [[Futility Pruning]]
* [[Lazy SMP]]
* [[Razoring]]
=Forum Posts=
==1995 ...==
* [http://groups.google.com/group/rec.games.chess.computer/browse_frm/thread/12607986c47b8ef6 approximate eval function] by [[Joël Rivat]], [[Computer Chess Forums|rgcc]], September 20, 1995
==2000 ...==
* [https://www.stmintz.com/ccc/index.php?id=110681 Caution K v KBN and lazy eval or futility] by [[Brian Richardson]], [[CCC]], May 14, 2000 » [[KBNK Endgame]], [[Futility Pruning]]
* [https://www.stmintz.com/ccc/index.php?id=192813 Chess Programming: "lazy eval"] by [[Matthias Gemuh]], [[CCC]], October 11, 2001
==2010 ...==
* [http://www.talkchess.com/forum/viewtopic.php?t=37223 doing lazy exit in eval or better not ?] by [[Engin Üstün]], [[CCC]], December 22, 2010
* [http://www.talkchess.com/forum/viewtopic.php?t=38499 lazy eval discussion] by [[Robert Hyatt]], [[CCC]], March 21, 2011
* [http://www.talkchess.com/forum/viewtopic.php?t=41236 Lazy eval] by [[Larry Kaufman]], [[CCC]], November 27, 2011
* [http://www.talkchess.com/forum/viewtopic.php?t=46130 Razoring / Lazy eval question] by [[Jerry Donald]], [[CCC]], November 24, 2012 » [[Razoring]]
* [http://www.talkchess.com/forum/viewtopic.php?t=52676&start=28 Re: lazy eval] by [[Jon Dart]], [[CCC]], June 19, 2014
* [http://www.talkchess.com/forum/viewtopic.php?t=53199 Lazy evaluation] by [[Robert Hyatt]], [[CCC]], August 07, 2014
* [http://www.talkchess.com/forum/viewtopic.php?t=54387 Implications of Lazy eval on Don Beal effect in Fail Soft] by [[Henk van den Belt]], [[CCC]], November 19, 2014 » [[Fail-Soft]]
==2015 ...==
* [http://www.talkchess.com/forum/viewtopic.php?t=64674 Is expensive eval required for QS?] by [[Alexandru Mosoi]], [[CCC]], July 21, 2017 » [[Quiescence Search]]
* [http://www.talkchess.com/forum/viewtopic.php?t=65047 adaptive lazy eval] by [[Ed Schroder]], [[CCC]], August 31, 2017
=External Links=
* [http://www.top-5000.nl/authors/rebel/chess840.htm#LAZY%20EVAL Search Techniques in REBEL (Lazy Eval)] from [http://www.top-5000.nl/authors/rebel/chess840.htm How Rebel Plays Chess] by [[Ed Schroder|Ed Schröder]] » [[Incremental Updates]], [[Rebel]]
* [http://macechess.blogspot.de/2014/06/not-being-lazy-anymore.html Not being lazy anymore ] by [[Thomas Petzke]], [http://macechess.blogspot.de/ mACE Chess], June 28, 2014 » [[iCE]]
* [https://en.wikipedia.org/wiki/Lazy_evaluation Lazy evaluation from Wikipedia] as general programming term
* [[Videos#DeepPurple|Deep Purple]] - [https://en.wikipedia.org/wiki/Lazy_%28Deep_Purple_song%29 Lazy] ([https://www.setlist.fm/setlist/deep-purple/1984/sydney-entertainment-centre-sydney-australia-4bde3f66.html Sydney 1984]), [https://en.wikipedia.org/wiki/YouTube YouTube] Video
: {{#evu:https://www.youtube.com/watch?v=iFSKvWICseQ|alignment=left|valignment=top}}
=References=
<references />
'''[[Evaluation|Up one Level]]'''
[[FILE:Naturgeschichte und Abbildungen der Reptilien (6059239621).jpg|border|right|thumb|[https://en.wikipedia.org/wiki/Chameleon Chameleons] <ref> [https://en.wikipedia.org/wiki/Chameleon Chameleons], [https://commons.wikimedia.org/wiki/File:Naturgeschichte_und_Abbildungen_der_Reptilien_(6059239621).jpg Plate 99] from [https://en.wikipedia.org/wiki/Heinrich_Rudolf_Schinz Heinrich Rudolf Schinz] ('''1833'''). ''Naturgeschichte und Abbildungen der Reptilien''. lithograph by [https://en.wikipedia.org/wiki/Karl_Joseph_Brodtmann Karl Joseph Brodtmann], [https://en.wikipedia.org/wiki/Wikimedia_Commons Wikimedia Commons]</ref> ]]
In the chess programming sense of the phrase <ref>In general computer programming, [https://en.wikipedia.org/wiki/Lazy_evaluation Lazy evaluation] refers a technique of delaying a computation until the result is required.</ref>, '''Lazy Evaluation''' means dividing all the tasks performed by [[Evaluation function|evaluation function]] in (usually two) stages. If after performing all the tasks for a given stage score exceeds [[Beta|beta]] by a certain margin or if it falls below [[Alpha|alpha]] by the same margin, the score is returned and no more evaluation is conducted. The first stage usually consists of the evaluation terms that are relatively cheap, possibly [[Incremental Updates|incrementally updated]], like [[Material|material]] and [[Piece-Square Tables|piece-square tables]]. Lazy evaluation may be viewed as taking the [[Alpha-Beta|alpha-beta]] principle one step further. If some parts of the evaluation function are omitted due to this heuristics, it means that one side is already winning "the evaluation game" by the margin unacceptable to the opponent, and therefore a cutoff occurs.
=See also=
* [[CPW-Engine_eval]]
* [[Rookie#Evaluation|Evaluation in Rookie 2.0]]
* [[Futility Pruning]]
* [[Lazy SMP]]
* [[Razoring]]
=Forum Posts=
==1995 ...==
* [http://groups.google.com/group/rec.games.chess.computer/browse_frm/thread/12607986c47b8ef6 approximate eval function] by [[Joël Rivat]], [[Computer Chess Forums|rgcc]], September 20, 1995
==2000 ...==
* [https://www.stmintz.com/ccc/index.php?id=110681 Caution K v KBN and lazy eval or futility] by [[Brian Richardson]], [[CCC]], May 14, 2000 » [[KBNK Endgame]], [[Futility Pruning]]
* [https://www.stmintz.com/ccc/index.php?id=192813 Chess Programming: "lazy eval"] by [[Matthias Gemuh]], [[CCC]], October 11, 2001
==2010 ...==
* [http://www.talkchess.com/forum/viewtopic.php?t=37223 doing lazy exit in eval or better not ?] by [[Engin Üstün]], [[CCC]], December 22, 2010
* [http://www.talkchess.com/forum/viewtopic.php?t=38499 lazy eval discussion] by [[Robert Hyatt]], [[CCC]], March 21, 2011
* [http://www.talkchess.com/forum/viewtopic.php?t=41236 Lazy eval] by [[Larry Kaufman]], [[CCC]], November 27, 2011
* [http://www.talkchess.com/forum/viewtopic.php?t=46130 Razoring / Lazy eval question] by [[Jerry Donald]], [[CCC]], November 24, 2012 » [[Razoring]]
* [http://www.talkchess.com/forum/viewtopic.php?t=52676&start=28 Re: lazy eval] by [[Jon Dart]], [[CCC]], June 19, 2014
* [http://www.talkchess.com/forum/viewtopic.php?t=53199 Lazy evaluation] by [[Robert Hyatt]], [[CCC]], August 07, 2014
* [http://www.talkchess.com/forum/viewtopic.php?t=54387 Implications of Lazy eval on Don Beal effect in Fail Soft] by [[Henk van den Belt]], [[CCC]], November 19, 2014 » [[Fail-Soft]]
==2015 ...==
* [http://www.talkchess.com/forum/viewtopic.php?t=64674 Is expensive eval required for QS?] by [[Alexandru Mosoi]], [[CCC]], July 21, 2017 » [[Quiescence Search]]
* [http://www.talkchess.com/forum/viewtopic.php?t=65047 adaptive lazy eval] by [[Ed Schroder]], [[CCC]], August 31, 2017
=External Links=
* [http://www.top-5000.nl/authors/rebel/chess840.htm#LAZY%20EVAL Search Techniques in REBEL (Lazy Eval)] from [http://www.top-5000.nl/authors/rebel/chess840.htm How Rebel Plays Chess] by [[Ed Schroder|Ed Schröder]] » [[Incremental Updates]], [[Rebel]]
* [http://macechess.blogspot.de/2014/06/not-being-lazy-anymore.html Not being lazy anymore ] by [[Thomas Petzke]], [http://macechess.blogspot.de/ mACE Chess], June 28, 2014 » [[iCE]]
* [https://en.wikipedia.org/wiki/Lazy_evaluation Lazy evaluation from Wikipedia] as general programming term
* [[Videos#DeepPurple|Deep Purple]] - [https://en.wikipedia.org/wiki/Lazy_%28Deep_Purple_song%29 Lazy] ([https://www.setlist.fm/setlist/deep-purple/1984/sydney-entertainment-centre-sydney-australia-4bde3f66.html Sydney 1984]), [https://en.wikipedia.org/wiki/YouTube YouTube] Video
: {{#evu:https://www.youtube.com/watch?v=iFSKvWICseQ|alignment=left|valignment=top}}
=References=
<references />
'''[[Evaluation|Up one Level]]'''
