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Reductions (as opposed to pruning),
a class of search heuristics that decrease the depth to which a certain branch of the tree is searched, also interpreted as negative extension.
Contents
Recursive Reductions
- Late Move Reductions - LMR
- Internal Iterative Reductions - IIR
- Fail-High Reductions - FHR
- Null Move Reductions
- RankCut
Near the Tips
Pruning after a reduced Search
Some dynamic pruning techniques base their pruning decision on a reduced search by factor R, also applied recursively:
A none recursive pruning based on reduction at some fixed depth is applied by:
See also
Forum Posts
1998 ...
- A new selective heuristic? by Frank Schneider, CCC, June 21, 1998
2000 ...
- Evaluation-based Reductions and/or Extensions by Tom Likens, CCC, December 28, 2003 » Extensions
- extensions + reductions + pruning = confusion by Johan de Koning, CCC, March 24, 2004 (was Shredder 8 secret: search depth?)
2005 ...
- Reductions and null move refutations by Tord Romstad, Winboard Forum, April 18, 2005 » Null Move Pruning
- Has anyone tested Gambit Fruit with Rebel Reductions on? by Ryan B., CCC, November 15, 2005 » Rebel, Gambit Fruit 1
- Reducing King Moves? by mjlef, Winboard Forum, January 03, 2007
- Toga/Glaurung/Strelka Prunings/Reductions by Edsel Apostol, CCC, January 31, 2008 » Toga, Glaurung, Strelka, Pruning
2010 ...
- Reducing/Pruning Bad Captures (SEE < 0) by Edsel Apostol, CCC, August 19, 2011 » SEE
- Reductions from internal iterative deepening by Evert Glebbeek, CCC, August 20, 2012 » Internal Iterative Deepening
- Houdini 3 reducing the depth feature by Maurizio Maglio, CCC, October 17, 2012 » Houdini
- Pruning in PV nodes by Sergei S. Markoff, CCC, January 14, 2014 » Root, Node Types
- variable reductions by Robert Hyatt, CCC, June 22, 2014
2015 ...
- Ratio reduction by Steven Edwards, CCC, September 20, 2015 » Late Move Reductions, Symbolic
- Reduction Research Question by Dennis Sceviour, CCC, September 25, 2015
- Reductions by Harm Geert Muller, CCC, May 22, 2016
- EMR & EMP by Michael Sherwin, CCC, July 19, 2016
- Floating Move Reduction by Dennis Sceviour, CCC, September 14, 2016
- EMR based on Null Move threat by Michael Sherwin, CCC, October 30, 2017
2020 ...
- Pruning / reduction depending on king safety by Vivien Clauzon, CCC, February 02, 2020 » King Safety
- An alternative to IID by Ed Schröder, CCC, August 13, 2020 » IID
- Futility reductions by Jost Triller, CCC, July 05, 2021 » Futility Pruning
External Links
- Reduction from Wikipedia
- Programmer Corner - How Rebel Plays Chess - Reductions by Ed Schröder (Wayback Machine), pdf reprint