Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Researching after a fail-low

Author: Robert Hyatt

Date: 06:23:38 08/18/00

Go up one level in this thread


On August 17, 2000 at 18:05:41, Gian-Carlo Pascutto wrote:

>On August 17, 2000 at 14:43:08, J. Wesley Cleveland wrote:
>
>>When you have a fail-low in a deep search where the value drops significantly,
>>finding an alternate move can take a very long time. This is largely because >the
>>values in the hash table are largely useless, so in effect we are researching
>>the entire tree. It seems to me one should use iterative deepening, and start
>>from ply 1 again.
>
>This technique has been described by Schaeffer a long time ago...
>
>(Obvious question: Why is nearly no-one doing it?)
>
>--
>GCP


I'm not sure what you mean by described a long time ago.  But there is a big
problem.  If you start over at 1 ply, you don't get the fail low score.  You
find (again) the _wrong_ move, until you get deep enough.  When there is a big
score swing between two iterations, you take your lumps.  There is no way to
cheat alpha/beta there.



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.