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Subject: Re: UPDATE: This is a null-move problem...

Author: Andrew Williams

Date: 05:26:06 06/27/02

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On June 26, 2002 at 16:21:11, Dieter Buerssner wrote:

>On June 26, 2002 at 13:53:11, Andrew Williams wrote:
>
>>This is a null-move problem, caused by a stupid bug in PM. My null-move
>>verification search was not working in this position. Now that I've fixed it,
>>this particular error doesn't occur. I'm still interested in what others see
>>here.
>
>For Yace, I cannot see much influence of null move here. I tried without null
>moves at all, with default null move usage (R=2, including a verification
>search) and with R=2 without any verification search. Each time I see a big fail
>low at depth 9 for Kg3. Of course without null move, many more nodes are used.
>Without verification search, somewhat less nodes are used than in the analysis
>shown here.
>

This is interesting. For PM, if I make my null-moving less agressive (ie don't
null move as much with few pieces, or don't use R=3 if there are few pieces), it
sees the problem pretty much immediately. But with PM's default null move
settings, it takes a *very* long time to see the problem. No matter what else I
do, PM doesn't react until ply 12.

Hmmmm.. perhaps 9 days before WCCC isn't the best time to radically re-think my
null move strategy!!

Thanks for your response.

Andrew




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