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Created page with "'''Home * Search * Depth Reduction R''' '''R''' is a common name for a constant or variable signifying depth reduction used in the Null Move Pru..."
'''[[Main Page|Home]] * [[Search]] * Depth Reduction R'''
'''R''' is a common name for a constant or variable signifying [[Depth|depth]] reduction used in the [[Null Move Pruning]] <ref>[[Chrilly Donninger]]. ('''1993'''). ''Null Move and Deep Search: Selective-Search Heuristics for Obtuse Chess Programs.'' [[ICGA Journal#16_3|ICCA Journal, Vol. 16, No. 3]]</ref>, [[Null Move Reductions]] and independently in [[Multi-Cut]] <ref>[[Yngvi Björnsson]], [[Tony Marsland]] ('''2001'''). ''Multi-cut Alpha-Beta Pruning in Game Tree Search.'' Theoretical Computer Science, Vol. 252</ref>. In many null move implementations it is either 2 or 3, the exact formula being <span style="background-color: rgb(199, 199, 199)">depth - R - 1</span>.
=Variable Reduction=
When '''R''' becomes a variable, then we say that a program uses [[Null Move Pruning#AdaptiveNullMovePruning|adaptive null move pruning]], first described by [[Ernst A. Heinz]] <ref>[[Ernst A. Heinz]]. ('''1999'''). ''Adaptive null-move pruning''. [[ICGA Journal#22_3|ICCA Journal, Vol. 22, No 3]]</ref>, using R=3 when normal search depth exceeds 6 plies and R=2 otherwise, while more recently most engines account increased search depth with greater reductions <ref>[http://www.talkchess.com/forum/viewtopic.php?t=64927 Rethinking r in null move] by [[Michael Sherwin]], [[CCC]], August 18, 2017</ref>.
=Forum Posts=
==1997 ...==
* [https://groups.google.com/d/msg/rec.games.chess.computer/JJTEBafyuYM/hRTys0ZxcUIJ Null move depth reductions] by [[Tom King]], [[Computer Chess Forums|rgcc]], February 02, 1997
* [https://www.stmintz.com/ccc/index.php?id=28772 Null move reductions] by [[Roberto Waldteufel]], [[CCC]], October 04, 1998
==2000 ...==
* [https://www.stmintz.com/ccc/index.php?id=183089 Null move R=2 vs Null move R=2/3] by [[Tom King]], [[CCC]], August 09, 2001
* [https://www.stmintz.com/ccc/index.php?id=239907 Null-Move: Difference between R = 2 and R = 3 in action] by [[Omid David]], [[CCC]], July 11, 2002
* [http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=313492&t=31361 Smooth scaling -- an explanation] by [[Dann Corbit]], [[CCC]], December 30, 2009
==2010 ...==
* [http://www.talkchess.com/forum/viewtopic.php?t=31436 Figuring out the R factor] by [[Michael Sherwin]], [[CCC]], January 03, 2010
* [http://www.talkchess.com/forum/viewtopic.php?t=49558 How much to reduce ?] by [[Henk van den Belt]], [[CCC]], October 03, 2013 » [[Late Move Reductions]]
* [http://www.talkchess.com/forum/viewtopic.php?t=60240 Reductions] by [[Harm Geert Muller]], [[CCC]], May 22, 2016 » [[Late Move Reductions]]
* [http://www.talkchess.com/forum/viewtopic.php?t=60561 Calculating R value for Null Move] by [[Andrew Grant]], [[CCC]], June 23, 2016
* [http://www.talkchess.com/forum/viewtopic.php?t=64927 Rethinking r in null move] by [[Michael Sherwin]], [[CCC]], August 18, 2017
* [http://www.talkchess.com/forum/viewtopic.php?t=65351 Update on null move and LMR] by [[Michael Sherwin]], [[CCC]], October 01, 2017 » [[RomiChess]]
=References=
<references />
'''[[Search|Up one Level]]'''
'''R''' is a common name for a constant or variable signifying [[Depth|depth]] reduction used in the [[Null Move Pruning]] <ref>[[Chrilly Donninger]]. ('''1993'''). ''Null Move and Deep Search: Selective-Search Heuristics for Obtuse Chess Programs.'' [[ICGA Journal#16_3|ICCA Journal, Vol. 16, No. 3]]</ref>, [[Null Move Reductions]] and independently in [[Multi-Cut]] <ref>[[Yngvi Björnsson]], [[Tony Marsland]] ('''2001'''). ''Multi-cut Alpha-Beta Pruning in Game Tree Search.'' Theoretical Computer Science, Vol. 252</ref>. In many null move implementations it is either 2 or 3, the exact formula being <span style="background-color: rgb(199, 199, 199)">depth - R - 1</span>.
=Variable Reduction=
When '''R''' becomes a variable, then we say that a program uses [[Null Move Pruning#AdaptiveNullMovePruning|adaptive null move pruning]], first described by [[Ernst A. Heinz]] <ref>[[Ernst A. Heinz]]. ('''1999'''). ''Adaptive null-move pruning''. [[ICGA Journal#22_3|ICCA Journal, Vol. 22, No 3]]</ref>, using R=3 when normal search depth exceeds 6 plies and R=2 otherwise, while more recently most engines account increased search depth with greater reductions <ref>[http://www.talkchess.com/forum/viewtopic.php?t=64927 Rethinking r in null move] by [[Michael Sherwin]], [[CCC]], August 18, 2017</ref>.
=Forum Posts=
==1997 ...==
* [https://groups.google.com/d/msg/rec.games.chess.computer/JJTEBafyuYM/hRTys0ZxcUIJ Null move depth reductions] by [[Tom King]], [[Computer Chess Forums|rgcc]], February 02, 1997
* [https://www.stmintz.com/ccc/index.php?id=28772 Null move reductions] by [[Roberto Waldteufel]], [[CCC]], October 04, 1998
==2000 ...==
* [https://www.stmintz.com/ccc/index.php?id=183089 Null move R=2 vs Null move R=2/3] by [[Tom King]], [[CCC]], August 09, 2001
* [https://www.stmintz.com/ccc/index.php?id=239907 Null-Move: Difference between R = 2 and R = 3 in action] by [[Omid David]], [[CCC]], July 11, 2002
* [http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=313492&t=31361 Smooth scaling -- an explanation] by [[Dann Corbit]], [[CCC]], December 30, 2009
==2010 ...==
* [http://www.talkchess.com/forum/viewtopic.php?t=31436 Figuring out the R factor] by [[Michael Sherwin]], [[CCC]], January 03, 2010
* [http://www.talkchess.com/forum/viewtopic.php?t=49558 How much to reduce ?] by [[Henk van den Belt]], [[CCC]], October 03, 2013 » [[Late Move Reductions]]
* [http://www.talkchess.com/forum/viewtopic.php?t=60240 Reductions] by [[Harm Geert Muller]], [[CCC]], May 22, 2016 » [[Late Move Reductions]]
* [http://www.talkchess.com/forum/viewtopic.php?t=60561 Calculating R value for Null Move] by [[Andrew Grant]], [[CCC]], June 23, 2016
* [http://www.talkchess.com/forum/viewtopic.php?t=64927 Rethinking r in null move] by [[Michael Sherwin]], [[CCC]], August 18, 2017
* [http://www.talkchess.com/forum/viewtopic.php?t=65351 Update on null move and LMR] by [[Michael Sherwin]], [[CCC]], October 01, 2017 » [[RomiChess]]
=References=
<references />
'''[[Search|Up one Level]]'''
