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Subject: Re: An improvement to null move search

Author: Vincent Diepeveen

Date: 11:06:37 04/07/04

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On April 07, 2004 at 04:06:38, Tord Romstad wrote:

>The following idea is still untested, but unless I am missing something it
>is guaranteed to reduce the number of nodes without any risk.  The idea is
>fairly obvious, and I am sure some of you are already using it, but I still
>don't think it is widely known.
>
>At a node where the remaining depth is sufficiently big that a null move
>would not drop us directly into the qsearch, and beta > DRAW_SCORE, avoid
>doing a null move search if the move leading to the node was a reversible
>move.  The point is that we know that the null move search is a waste of
>time in this case.  After the null move, the opponent can just reverse
>his move, with a repetition draw score.
>
>Tord

In diep nullmove has the same effect upon the 2 fold repetition like a pawn
move.

I guess now you will search even deeper because you really want a fail low :)



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