Difference between revisions of "Fail-Low"
GerdIsenberg (talk | contribs) (Created page with "'''Home * Search * Alpha-Beta * Fail-Low''' FILE:Going down ?.jpg|border|right|thumb|Going down? <ref>[https://commons.wikimedia.org/wiki/File:Going_d...") |
GerdIsenberg (talk | contribs) m |
||
| Line 1: | Line 1: | ||
'''[[Main Page|Home]] * [[Search]] * [[Alpha-Beta]] * Fail-Low''' | '''[[Main Page|Home]] * [[Search]] * [[Alpha-Beta]] * Fail-Low''' | ||
| − | [[FILE:Going down ?.jpg|border|right|thumb|Going down? <ref>[https://commons.wikimedia.org/wiki/File:Going_down_%3F.jpg Going down? | + | [[FILE:Going down ?.jpg|border|right|thumb|Going down? <ref>[https://commons.wikimedia.org/wiki/File:Going_down_%3F.jpg Going down?] [https://en.wikipedia.org/wiki/Camden_Fort_Meagher Camden Fort Meagher] by Twhelton, February 9, 2013, [https://en.wikipedia.org/wiki/Wikimedia_Commons Wikimedia Commons]</ref> ]] |
There are two related semantics, if talking of a '''Fail-Low''' - inside the [[Search Tree|search tree]] or if using [[Aspiration Windows|aspiration windows]] at the [[Root|root]]. | There are two related semantics, if talking of a '''Fail-Low''' - inside the [[Search Tree|search tree]] or if using [[Aspiration Windows|aspiration windows]] at the [[Root|root]]. | ||
Revision as of 09:55, 3 May 2018
Home * Search * Alpha-Beta * Fail-Low
Going down? [1]
There are two related semantics, if talking of a Fail-Low - inside the search tree or if using aspiration windows at the root.
Contents
Inside the Tree
A Fail-low appears at so called All-Nodes inside the alpha-beta algorithm, also called Fail-Low nodes. The score returned is a upper bound on the exact score of the node.
Quote by Bruce Moreland [2]:
A fail-low indicates that this position was not good enough for us. We will not reach this position, because we have some other means of reaching a position that is better. We will not make the move that allowed the opponent to put us in this position.
Root with Aspiration
Another meaning of a Fail-Low, is associated with aspiration windows at the root, where one needs to re-search with wider windows to get the true score rather than an upper bound.
Bruce again:
You can also talk about failing high and failing low from the root position, if you use an aspiration window.
See also
Forum Posts
1995 ...
- Failing low at the root by Guido Schimmels, CCC, August 03, 1998
- Question: Fail High then Low at Root by William Bryant, CCC, December 28, 1999 » Fail-High, Root, Search Instability
2000 ...
- Question: Fail low at root and time management by William Bryant, CCC, February 08, 2000 » Root, Time Management
- Fail-Low ? by Nobuhiro Yoshimura, CCC, April 05, 2000
- Researching after a fail-low by J. Wesley Cleveland, CCC, August 17, 2000
- Fail highs..which subsequently fail low by Tom King, CCC, August 27, 2000 » Fail-High, Search Instability
- Researching after a deep fail low by José Carlos, CCC, September 24, 2001
- MTD, IID, fail-low, root-research by Juergen Wolf, CCC, August 14, 2003 » MTD(f), Internal Iterative Deepening, Root
- Search behavior in a case of root fail high/low by Sergei S. Markoff, CCC, March 10, 2004 » Fail-High, MTD(f)
2005 ...
- Fail-low pruning by Tommi Rimpiläinen, CCC, January 17, 2006
2010 ...
- Fail soft vs fail hard by Sergei S. Markoff, CCC, February 15, 2014 » Fail-Soft, Fail-Hard, Internal Iterative Deepening
- Solving a fail low situation at the root by Alberto Sanjuan, CCC, November 03, 2014 » Aspiration Windows
- What does "fail low at the root" mean? by watersky33, OpenChess Forum, December 24, 2014
2015 ...
- Fail low after fail high by J. Wesley Cleveland, CCC, April 04, 2015 » Fail-High, Search Instability
- Restarting iterative deepening by Harm Geert Muller, CCC, December 09, 2015 » Aspiration Windows, Iterative Deepening
- (I)ID and PV dropout by Harm Geert Muller, CCC, June 17, 2017 » Internal Iterative Deepening, Iterative Deepening
External Links
- Programming - Glossary - Fail Low, Fail High from Bruce Moreland's Programming Topics Site
- The Beatles - I'm Down (1966), YouTube Video
- Stevie Ray Vaughan [3] with Jeff Beck and Terry Bozzio - I'm Going Down (1989), YouTube Video
References
- ↑ Going down? Camden Fort Meagher by Twhelton, February 9, 2013, Wikimedia Commons
- ↑ Programming - Glossary - Fail Low, Fail High from Bruce Moreland's Programming Topics Site
- ↑ Naresh Vempala, Subrata Dasgupta (2007). A Computational Model of the Music of Stevie Ray Vaughan. pdf
