Author: Martin Giepmans
Date: 08:37:25 11/23/02
Go up one level in this thread
On November 23, 2002 at 08:48:36, Omid David Tabibi wrote: >On November 23, 2002 at 08:45:00, Uri Blass wrote: > >>On November 23, 2002 at 08:11:37, scott farrell wrote: >> >>>Just after other people's thoughts. >>> >>>I think Omid's work overlooked the adapative null move searching many of us do, >>>ie. transitioning from r=3 to r=2. >>> >>>I think adaptive null move tries to GUESS where to use r=2 to reduce the errors >>>that R=3 makes. I guess it depends on how often this GUESS is correct, the cost >>>of the verification search, and how long it takes the adaptive searching to >>>catch the error at the next ply. >>> >>>Has anyone looked at setting the verification search to reduced depth of 2 >>>(rather than 1)? obviously to reduce the cost of the verification search. >> >>Omid checked it but you also reduce the gain. >> >>I think that I will look for good rules when to do the verification search so >>the cost will be significantly smaller but the gain is going to be the same in >>at least 99% of the cases. >> > >I'm currently working on other variations. The initial results are promising. > >>Uri I have done some tests with your method at greater depths. At depth 12 vrfd R=3 still had an overhead (in terms of treesize) of about 25% compared to pure R=3. (my engine uses a simple Q-search that shouldn't give problems here) So the question is if your expectation that the treesize of R=3 and vrfd R=3 converge at greater depths (> 11) really holds. Needs more testing, I think. Another point: I would expect that vrfd R=3 becomes less safe at greater depths. The subtrees in which you don't verify nullmove (after the verification) become deeper and I see no reason - on logical grounds - why this shouldn't give safety problems. Even if R=3 and vrfd R=3 converge in terms of treesize, the safety (or rather the lack of it) might also converge ... In any case, thanks for sharing. Martin
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