Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Fail high reductions

Author: Uri Blass

Date: 15:10:04 07/01/03

Go up one level in this thread


On July 01, 2003 at 17:34:47, Russell Reagan wrote:

>From "Fail High Reductions by Rainer Feldmann"
>
>"...a fail high node is a node 'v' with a search window of [alpha,beta] at which
>a static evaluation function 'c' produces a cutoff. The FHR-algorithm reduces
>the search depths at these fail high nodes thus searching their subtrees with
>less effort."
>
>Their subtrees? I thought fail high nodes didn't have subtrees, and that you
>return beta at a fail high node. I must be misunderstanding something. Could
>someone give a simple explaination of how fail high reductions work?

If I understand correctly the idea is that you evaluate a position that is not a
leaf and the static evaluation is not in the window of [alpha,beta] so you
reduce the depth.

Example:when you analyze e4 Nf6 Qh5 Nxh5 your evaluation is a queen advantage
for black and you can be almost sure of fail high so instead of searching to
remaining depth of 7 you may decide to search to a smaller depth.

Uri



This page took 0.03 seconds to execute

Last modified: Thu, 07 Jul 11 08:48:38 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.