Author: Jeremiah Penery
Date: 06:13:49 11/09/03
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On November 09, 2003 at 04:55:40, Matthias Gemuh wrote: >>Anyway my question is since you go directly to quiescent search >>(where stand pat cutoff of all futile moves occur) after making the move, >>we only saved ourselves "making of the futile moves".I can comprehend the >>extended futlity pruning but not this.For me as long as standing pat cut off >>is there , futility pruning at frontier is unnecessary,and if it is,it only >>saves the time to make and unmake futile moves.Where does the 60% tree shrinkage >>comes from?Please try to see where my proble is. > >Your logic seems sound for me. We seem to save only >MakeMove() + UnmakeMove() + Evaluate(). The difference of pruning before or after making the move is probably very tiny, assuming you always prune the same nodes. The 60% savings must come from the entire act of pruning. Depth 1 in the tree is by far the widest point in the tree. Also, it is possible that extensions could trigger there, making it even larger. qsearch() also contains a large part of the total searched nodes. Pruning all of these things away in many branches can easily result in 60% lowering of tree size.
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