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Subject: Re: Static Exchange Evaluation (SEE) for pruning in quiescence (?)

Author: Joost Buijs

Date: 03:19:59 08/19/03

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On August 19, 2003 at 04:12:45, Tord Romstad wrote:

>On August 19, 2003 at 02:48:36, Omid David Tabibi wrote:
>
>>It seems that some programs use Static Exchange Evaluation in order to prune
>>losing captures in quiescence search.
>
>Not just some.  Almost all strong programs do this, I think.
>
>>In the following position, an SEE will deem the move 1.Rxd7 a losing capture, and it might
>>get pruned in quiescence. However, in fact this is a winning capture since Qf6 is attacked
>>after 1.Rxd7. How do such programs solve these kind of problems?
>
>They don't (or at least most don't).  On the other hand, the significant extra
>speed gained
>by not searching all captures help them find a lot of other tactics which they
>otherwise
>wouldn't have found.
>
>Try it yourself.  I am almost certain that you will find that excluding losing
>captures
>from the qsearch is a big win.

To me it looks wrong to skip losing captures from the quiescence search if the
losing captures are determined by a SEE that is wrong in some cases, e.g. pinned
pieces. If you use the SEE for move ordering purposes only this problem doesn't
exist.

>
>Tord



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