Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: null move and draw detection

Author: Robert Hyatt

Date: 11:01:39 12/11/02

Go up one level in this thread


On December 11, 2002 at 07:45:37, scott farrell wrote:

>What does the detection of a draw during a Null Move Search mean? Can you
>cut-off based on the score being a DRAWSCORE that comes back from the nullsearch
>if it is >=BETA?
>
>I think the meaning is undetermined, and is a probably related to ZUGS.

I treat it as a normal thing.  IE when I "make" a null move, I update the hash
signature so that positions below the null-move can't possibly match with
positions above the null-move (unless another null-move is made of course).

Then "real" repetitions can't happen, but if, below a null-move you find a
repetition,
then you know it started and ended after the null-move so a draw score is
perfectly
reasonable.




>
>I just changed my code, such that if a draw it detected during a nullmove, I
>return ILLEGAL straight away.
>
>I guess it depends on the type of draw detected:
>
>StaleMate - this is the clear ZUG
>Repitition - maybe I should even really be checking for draw by rep during null
>move search
>NM - not enough material.
>
>What do other people do in their engines?
>
>Ideas much appreciated
>Scott



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.