Author: Ulrich Tuerke
Date: 06:54:55 04/24/01
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On April 24, 2001 at 09:41:37, JW de Kort wrote: >On April 23, 2001 at 06:45:35, Ulrich Tuerke wrote: > >>On April 23, 2001 at 05:52:00, JW de Kort wrote: >> >>>Dear friends, >>> >>>I have added a qsearch to my program and as a result the number of nodes in my >>>search has exploded. Sometimes the program searches ten times as much nodes in >>>the qsearch than in the regular search. Can anybody give me some advice on >>>methodes i can use to limit the number of nodes in the qsearch? >>> >>>Thanks in advance. >>> >>>Jan Willem >> >>In case of a capture move resulting in a score still considerably below the >>current value of alpha I cut the line. >> >>Uli > > >Dear Uli, > >does this mean that my program can stop the qsearch if the value after the best >capturing move has been tried is less then alpha. Something like: > >score = evaluation values after best move > >if score < alpha >stop Yes, that's the idea. I have something like if (!InCheck && !PawnEnding && score < alpha-PosThreshold) break; in the loop over all generated moves, i.e. this move will be skipped. Reasonable values for PosThreshold depend on the size of static evaluations which you are using. I guess, that values from PosThreshold = 1/2 pawn .. PosThreshold = 2 pawns could be reasonable for most programs. It's worth a bit of tesing. Regards, Uli
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