Author: Alessandro Damiani
Date: 03:46:31 11/09/03
Go up one level in this thread
On November 09, 2003 at 04:55:40, Matthias Gemuh wrote: >On November 09, 2003 at 03:53:24, Daniel Shawul wrote: > >> >> >>>I do not remember if Ernst's paper said that you make the move first and then >>>decide if it is futile. >>> >>>If it did, then it's definitely killing all the interest of futility pruning at >>>depth 1! >>> >>>The idea is to prune before you make the move. So you stay at depth==1, look at >>>the move, and say "hey, this move looks completely futile, let's ignore it!". >>> >>> >>> >>> Christophe >> >>A futile move is futile before you make or after you make it. >> before >> mat_bal + move_gain + margin < alpha => futile move >> after >> mat_bal + margin < alpha => futile move >>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. >> >>Daniel > > > >Your logic seems sound for me. We seem to save only >MakeMove() + UnmakeMove() + Evaluate(). > >/Matthias. Right. And if we use lazy eval then we save about the cost of "only" MakeMove() + UnmakeMove(). But we don't have to forget that most of the cost of a full-width search is caused at depth = 1. Alessandro
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