Author: Vincent Diepeveen
Date: 07:33:19 07/13/02
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On July 13, 2002 at 04:47:16, Omid David wrote: >On July 13, 2002 at 02:39:38, Dann Corbit wrote: > >>On July 13, 2002 at 02:22:00, Omid David wrote: >> >>>On July 13, 2002 at 02:07:17, Vincent Diepeveen wrote: >>> >>>>I still do not understand which positions you talk about which R=2 >>>>is finding and R=3 isn't. >>> >>>I read your other post, that's also my point: Although at fixed depth, R=2 is >>>much better than R=3 (see also "adaptive null-move pruning" Heinz 1999), in >>>practice R=3 performs about the same as R=2 since on many occasions it finds the >>>correct move one ply later with lower search cost. >> >>By the way, if you have not found Vincent's post on double null move you should >>look it up. It is a clear win for sure. > >Yes it's a nice idea. But the main null-move pruning deficiency is its tactical >weakness due to horizon effect. Zugzwangs are not a major problem, and as >Vincent points out, he invented the double null-move idea just to show that >null-move pruning is OK. Now nobody doubts effectiveness of null-move pruning at >all, the only discussion nowadays is the depth reduction value. I'm missing any position where you have a problem though. Seems to me your thing is incredible weak, and or doing other dubious things which gets looked up in hashtable, after which it weakens your program. In DIEP i don't have all these problems. - no dubious forward pruning - no futility - no razoring or any of these techniques. - checks in qsearch Just PVS with nullmove R=3 and a bunch of extensions. That's it. Means that after a nullmove i don't get transpositions to positions where you have stored a score which is based upon a dubious score. Best regards, Vincent
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