Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: qsearch questions

Author: Jon Dart

Date: 15:59:20 12/03/02

Go up one level in this thread


On December 03, 2002 at 17:16:58, Robert Hyatt wrote:

>
>the idea is to do anything you can to exclude moves.  Because below each move
>you search, you grow a tree, and that is expensive.  If alpha is 0.00, and
>the current material score is -15.0, then capturing a pawn is not going to
>help, and avoiding that capture avoids the tree below it.

I've noticed that Crafty uses the material value as a basis for calculating
futilty. In other words, if material + SEE gain + safety margin < alpha, you cut
the move (I do something similar at present).

What Mike is suggesting is to use the total position eval, which is also
something I've experimented with. So: if eval + capture + SEE gain + safety
margin < alpha, you cut. If you have large positional scores, this is possibly
safer (the "safety margin" in Crafty is only 1 pawn).

--Jon



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.