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Subject: Re: Another Embarassing Endgame Problem

Author: Gareth McCaughan

Date: 18:34:38 11/22/01

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On November 22, 2001 at 17:56:07, Colin Frayn wrote:

> I've been looking at static endgame evals again (i.e. no searching).
>
> I'm not sure how 18.12 manages, but Crafty 18.10 completely misevaluates
> this simple endgame position.  So does the current build of Beowulf.
> It's obviously a win for white, but yet both engines evaluate
> this position as a massive advantage to black.
>
>[D]8/1KPk4/8/6p1/p7/8/8/8 b - -

Think for a moment about how *you* evaluate this position as
"obviously a win for white". I bet the answer is that you
think "White will just push the pawn and queen; Black can't
take it". In other words, you do it by looking ahead: by
search. Why shouldn't programs do likewise?

I think most programs will look ahead one move "for free"
in this position as a result of pawn-push extensions, so
it's not as if they'll misevaluate something upstream by
stopping searching in the diagram position. So the only
reason for catching this in the static eval would be to
save execution time. That's a valid reason, but you have
to ask whether the time it saves is worth the time it
costs. It might well be, but I wouldn't make a large bet
on it.

--
g



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