Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: And a few additional questions.

Author: Bruce Moreland

Date: 18:49:30 11/26/00

Go up one level in this thread


On November 26, 2000 at 20:14:53, William Bryant wrote:

>On November 26, 2000 at 18:59:21, Bruce Moreland wrote:
>>>Let me add one thing to the good advice you gave in you other post.
>>>Skipping moves, that obviously cannot bring the score to alpha can have a few
>>>traps. I.e. say alpha is -0.5 and the stand-pat is -4.5 in KNPK. Capturing
>>>the last opponent pawn would not bring back the stand-pat to alpha, even not
>>>with a considerably large safety margin. Nevertheless, the score is 0.0 which is
>>>> alpha.
>>
>>Yes, there are some problems, and in fact I had this bug.  I simply turn this
>>off when there are only a few pieces.
>>
>>It's not perfect.  You could be giving a huge bonus for connected passed pawns,
>>and not allow one of them to be captured.
>>
>>bruce
>
>I think you lost me here, are you saying that when there are only a few pieces
>(pieces and pawns?) that you disable the null move portion of the QSearch.
>Specifically,
>	Score = eval();
>	if (Score >= beta)
>		return beta;
>So that you would change this to read
>	if ((Score >= beta) && (There are enough pieces on the board))
>		return beta;
>
>Thanks for clarifying this point.
>
>William
>wbryant@ix.netcom.com

When there are only a few pieces left on the board, I disable the very
aggressive pruning that my quiescent search normally uses.

There are no changes to the search pseudo-code example, the changes are in the
move generator.

bruce




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.