Author: James Robertson
Date: 08:20:54 09/08/99
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On September 08, 1999 at 09:49:07, Robert Hyatt wrote: I have had a terrible time trying to implement something like this, and finally gave up. How much does it help Crafty/Screamer? Is it worth it to try to get it to work? James >On September 07, 1999 at 22:52:10, William Bryant wrote: > >>I was reviewing my code, and noted in the root search when the score obtained >>is > alpha (and < beta) I was doing the following: >> >>alpha = score; >>beta = alpha + WindowSize; >> >>I thought this idea came from Crafty, but now I can't find it in the Crafty >>source. Further, although it makes the initial ply's slightly slower, it speeds >>up the search overall and improves the LCTII score as well. >> > >It is in SearchRoot(). I do it because after I fail high at the root, and >get a score, I don't want to continue searching root moves with beta=+infinity >as that can slow you down if the position is wild. > > > >>Question: >> Is there any harm in updating beta to the aspiration window size at the root >>when a score is backed up to the root and alpha is changed? >> >> Is this idea good, bad, neither? >> >> Did this come from Crafty at one point? > >It had better still be in there. :) Although I can't guarantee that it was >not removed for a version or two for testing something else. In the current >SearchRoot() (searchr.c) I find this at line 150: > > > alpha=value; > beta=value+40; > root_beta=beta; > > > >> >>Thanks. >> >>William >>wbryant@ix.netcom.com
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