Author: Robert Hyatt
Date: 16:05:12 01/25/01
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On January 25, 2001 at 12:49:58, Edward Screven wrote: >On January 25, 2001 at 09:34:05, Robert Hyatt wrote: > >>On January 25, 2001 at 08:20:26, David Rasmussen wrote: >>>I mean, maybe many of the "unsound" pruning methods would be sounder if, instead >>>of just pruning, they just adjusted the resulting depth down. In that way, a >>>line would still be examined, only later. >> >> >>This is what null-move search does, in essence... > >we must think about the null move heuristic differently, because i >don't think its typical implementation is at all similar to what >david suggested. > >sure, there is a reduced depth search involved, but it's part >of the pruning test, not the pruning action. the pruning action >is all or none -- completely prune the move from the parent node >or search it in full. Think about it differently. IE at ply=N, I play a move and I am about to do a normal search to depth=X to see how this move works. But first, I assume my opponent does nothing, and I then do a much shallower search with me to move again. If this is bad for me, there is no need for me to search this move to the full depth, I can get away with searching it to the shallower depth, proven by the null-move observation... > >applying david's suggestion to a null move implementation would >mean reducing the search depth after a null move failed high >instead of simply returning immediately with a fail high. > > - edward
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