Author: Robert Hyatt
Date: 13:54:03 09/27/04
Go up one level in this thread
On September 27, 2004 at 16:41:01, martin fierz wrote: >On September 27, 2004 at 16:36:33, Dan Honeycutt wrote: > >>On September 27, 2004 at 15:32:05, martin fierz wrote: >> >>>aloha! >>> >>>i just tried the following in my program: >>> >>>if a nullmove was tried and it failed, i saved a "nonull"-flag in my hashtable. >>>when i got a hash hit, i checked whether nonull was set or not, if it was not >>>set i did not attempt a nullmove. >>> >> >>I don't think you want to do that. Just because the null move failed at the >>current depth doesn't mean it will fail later at a different depth. >> >>Dan H. > >i know some people are doing this (among others bob), but i don't know exactly >when they do it, or why, and how much it helps. any answers are appreciated :-) > >cheers > martin I'm not quite doing that. What I do is this: When I get a hash hit, and the draft is not enough to let me stop the search at that point, I then test the table draft against the depth I would use for a null move search at this point. If the table draft is >= that depth, and the table entry says "No way I would fail high here" then there is no point in trying a null-move search, if a normal move search would not fail high... It's a well-known idea that I believe came from Murray Campbell of the deep blue/deep thought team...
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