Author: David Rasmussen
Date: 04:17:49 01/31/02
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On January 30, 2002 at 23:23:34, Robert Hyatt wrote: >On January 30, 2002 at 14:18:47, David Rasmussen wrote: > >>On January 30, 2002 at 10:12:25, Gian-Carlo Pascutto wrote: >> >>>Why are you blindly assuming that their effective branching factor >>>is 40, just because that is the average number of legal chess >>>moves? You should know better. And I know you do. >>> >>>They used PVS. Aspiration windows. Hashtables for the first TWELVE >>>plies. Even futility pruning. >>> >> >>Futility pruning? I don't think so. Hsu hated futility pruning, even in >>quiescence. >> >>/David > > >They _definitely_ used futility pruning in the hardware part of the search. >This was reported at several public presentations and was one of the features >they turned off to slow the processor down in the famous DB vs the micros >match... > >No idea if they used futility in the software search, but they definitely >used it in the hardware part as per their discussions... OK, I didn't know that. A newsgroup thread between you and Hsu from around 1990 seemed to indicate that he thought that your q-search FP was the reason of many tactical mistakes, and that he considered it to be extremely unsound. So I assumed it wasn't in DB. But hey, you live and learn. /David
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