Author: Tord Romstad
Date: 02:46:24 08/04/04
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Hi Cesar! On August 03, 2004 at 15:04:54, Cesar Contreras wrote: >I'm working on extended futility prunning and it's not working, it seems to >make a node reduction, but it plays worse than without it. > >My question is, do any of you have seen good improvement using extended >futility prunning? Yes, I use something very similar to extended futility pruning, with good results. The technique as explained by Heinz didn't work for me, but with some extra conditions added it performed much better. I never prune if there was an extension in one of the last two moves in the current line. This little extra condition, by the way, is useful also with many other pruning and reduction techniques. It greatly improves the program's tactical accuracy. I also never prune checks, passed pawn pushes to the 7th or 8th rank, or moves which threaten a valuable enemy piece. I don't prune if the side not to move has very bad king safety. >what normal futility margin do you use? >what extended futility margin do you use? 2 pawns and 5 pawns, but around the result of the last iteration rather than around alpha. Tord
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