Author: Robert Hyatt
Date: 17:00:49 08/04/99
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On August 04, 1999 at 16:32:10, Tom King wrote: >Hi all, > >What are the pro's and con's of using a static exchange evaluator (SEE) >for pruning captures in the Q. search? My program currently *doesn't* >use a SEE, but if I remember right, some programs like Crafty and Ferret >use a SEE to prune "losing" captures, i.e they examine a swap sequence on >a particular square, and if it appears to lose material, they prune that >capture right out. > >Who else is using a SEE in this way? I was playing around with this kind >of thing at the weekend, and I found that pruning these "losing" captures >is not without risk - some test problems are solved a ply later than normal >(for my program, anyhow, and this could be a bug in my SEE). On the other >hand, search speed is increased, sometimes quite dramatically. > >Opinions? Is pruning SEE losers in the Q. search a win? I find the following: using SEE to order captures in the q-search, without eliminating any, will shrink the tree about 10% over using something simple like MVV/LVA. But the SEE code will likely cost you more than 10% (unless you are a bitmap program where this can be done fairly efficiently). using SEE to eliminate losing captures can speed you up another 50%, or a factor of two, which is very significant. And no matter how slow your SEE code is, that become a 'winner' of an idea.
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