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Subject: Re: qsearch questions

Author: Robert Hyatt

Date: 14:16:58 12/03/02

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On December 03, 2002 at 15:58:44, Mike Adams wrote:

>I'm trying to understand the difference between reducing the overhead in qsearch
>and futility pruning.  On ply one of qsearch is it best to try all captures that
>can possibly change alpha without say using a SEE? And if the positional bonuses
>relative to a capture can only change by a max of say 100 can you safely say
>that if the value of the captured pieces plus the evaluation value you have when
>you entered qsearch plus 100 is less than alpha it need not be played? Should
>there also be a beta test? While i want speed an accurate qsearch is more
>important to me than a fast one.  My understanding is whatever you capture on
>ply 1 of qsearch you never improve your score beyond that.  On ply 3 of qsearch
>if you have an even better capture your opponent will pass to move on ply 2.
>thanks Mike Adams.


the idea is to do anything you can to exclude moves.  Because below each move
you search, you grow a tree, and that is expensive.  If alpha is 0.00, and
the current material score is -15.0, then capturing a pawn is not going to
help, and avoiding that capture avoids the tree below it.

I use SEE in the q-search to exclude captures that appear to be hopeless...



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