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Subject: Re: PushPP Comment Re: Interesting search extension data

Author: Robert Hyatt

Date: 08:07:53 01/25/01

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On January 25, 2001 at 09:42:16, Brian Richardson wrote:

>On January 24, 2001 at 23:39:12, Robert Hyatt wrote:
>
>>push passed pawns is an extension that is triggered if a passed pawn is pushed
>>to the 7th rank only.
>>pushpp
>>0.00 sum of times(squared)=29373
>>0.25 sum of times(squared)=29385
>>0.50 sum of times(squared)=29336
>>0.75 sum of times(squared)=29360
>>1.00 sum of times(squared)=29375
>>pushing a passed pawn had hardly any effect, but that might be a
>>result of the test suite rather than a useless extension.  The default
>>value for this is also .75
>>
>>
>
>Doesn't Crafty advance pawns in the evaluation anyway (until blocked or
>captured, I have not studied the code for some time), and then do its
>sophisticated passed pawn eval?  This might account for the negligible extension
>effect.  Just a thought.
>Brian


No, although if a pawn _is_ passed, the eval will understand if it is
unstoppable when the opponent has no pieces except a king that is too
far away.  However it seems (to me) that pushpp is fairly ineffective...
and that recapture is a lemon completely...



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