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Subject: Re: About SEE

Author: Severi Salminen

Date: 13:29:17 01/04/01

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On January 04, 2001 at 10:03:11, Robert Hyatt wrote:

>On January 04, 2001 at 04:05:02, Severi Salminen wrote:
>>I'm planning on programming SEE into my program today. I'd like to know whether
>>I "should" (well, of course I can do anything I want but) prune all losing
>>captures in qsearch or search them (after the good ones)? And what about equal
>>captures? What I mean is that if I prune, I get a speedup, but I lose a lot
>>positional info if that particular losing capture leads to (say) passed pawn or
>>similar. What do you do?
>I do something close to that.  I take the current material score, plus the
>'score' computed by SEE, plus a fudge factor, and ask "does this at least
>get close to or more than alpha?"  If yes, I search it.  IE if I am a queen
>down, then winning a pawn won't help and it is futile to search the move
>even though SEE says it wins a pawn.

So this is like doing a more accurate futility pruning in qsearch. Do you use
the same margin as in futility pruning (I use 2 pawns). If I have understood
right, futility pruning in normal search does only need to know the value of
piece being captured, not the true swapoff value so SEE doesn't help there.


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