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Subject: Re: SEE Result

Author: Tony Werten

Date: 07:42:20 08/12/04

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On August 12, 2004 at 10:18:45, Stuart Cracraft wrote:

>Here is the result of the 30 second per position test on 300 positions
>using nothing, see>=0 to search a capture, see having to bring the score
>within alpha and a margin (futility/delta), and with both.

I'm not sure how it is usually done, but I don't think it is safe to prune the
see score against alpha but rather the captured piece value. Else it makes your
qsearch even more blind.

Tony


>
>Nothing
>
>$ ./qaNbatch
>HERALD ga nosee30300.log 30 300
>**** 9.98/35.29 85% 255/300 7183.08 1793586432 5978621/24/249696 0/0/104784432/0
>/0/0
>
>see>=0 to search a capture
>
>HERALD ga -DSEEQUIESCE seequiesce30300.log 30 300
>**** 10.14/31.88 85% 257/300 7144.92 1599515136 5331717/24/223868 0/0/52093584/0
>/0/0
>
>see bringing score within alpha and a margin (futility/delta)
>
>HERALD ga -DDELTAPRUNE seedelta30300.log 30 300
>**** 9.98/35.27 85% 255/300 7183.00 1783053568 5943512/24/248232 0/0/104211232/0
>/0/0
>
>delta
>
>HERALD ga -DSEEQUIESCE -DDELTAPRUNE seeboth.log 30 300
>**** 10.14/31.87 85% 257/300 7144.30 1600962560 5336542/24/224089 0/0/52147264/0
>/0/0
>$
>
>So -DSEEQUIESCE and -DSEEQUIESCE -DDELTAPRUNE are the best with
>identical ply-depth scores of 10.14 ply and very nearly equal
>maximum capture-search depth of 31.88 and 31.87 plies. Other
>measurements are very similar as well.
>
>Neither nor both is much of an improvement over not having both,
>at least in this short test, however the search tree is smaller
>and the depth is 1/5 of a pawn deeper so those are good signs.
>The total nodes searched dropped by 10% but so did the nodes
>per second.
>
>Probably a better test than fixed time is fixed depth. On those,
>I've seen the SEEQUIESCE (see>=0 for capture search) look at
>50% fewer nodes in 50% less time as predicted by others. Not
>so sure about SEEDELTA.
>
>They don't seem as additive as I had hoped. However my SEEDELTA
>is implemented with a fixed MARGIN value of 1/5 of a pawn. I'll
>try it with the varying maximum positional score for the side on
>move and see if that improves things. I doubt it will make much
>of a difference.
>
>Stuart



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