Author: José Carlos
Date: 16:41:52 05/24/02
Go up one level in this thread
On May 24, 2002 at 18:14:57, J. Wesley Cleveland wrote: > I was looking at the source of crafty and saw that on a fail low, the value >returned is alpha, rather than Max of all the values from the level below. Is >there some disadvantage in returning the real upper bound? I think it causes >some problems in Crafty making it much slower resolving fail-highs and fail-lows >at the root as these branches all need to be re-searched. I use fail soft because I think (not tested) that it generates smaller trees generally. The drawback is that what you call "real upper bound" is no always so. Null move and hashing make the search return "not totally correct bounds" some times. It is very common that you fail high in the root, research with a different window and get a fail low. So fail hard makes search more stable (it's less probable to get such instabilities if you always return the search bounds). José C.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.