Author: Omid David
Date: 08:09:19 07/13/02
Go up one level in this thread
On July 13, 2002 at 10:33:19, Vincent Diepeveen wrote: >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 Why do you think there is a problem?! All the results I got are natural. I'm sure even in DIEP, R=2 works better under "fixed theoretical" conditions. However in practice you don't search to fixed depth and thus R=3 might be better in practice. My only point is that "R=3 might be better than most people consider it." (Take DIEP as a successful use of R=3) P.S. Have you published anything regarding double null-move?
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