Author: J. Wesley Cleveland
Date: 12:06:23 07/27/02
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On July 25, 2002 at 20:13:45, Robert Hyatt wrote: >On July 25, 2002 at 19:24:06, J. Wesley Cleveland wrote: > >>I see that crafty does not store lower bounds of MATE-n in the hash table, >>rather changes them to MATE-300. Bob wrote that he had search instabilities >>before he did this. Normally, this does not matter, but I think it makes crafty >>considerably slower in finding mates, as it only gets cutoffs on exact scores. >>Do other people have experience in this ? > > >Note that all this does is slightly decrease search efficiency. I do store >_exact_ mate scores as they should be stored. I store "bounds" that are based >on MATE as MATE-300. The penalty is _very_ small unless you have a position >where almost everything leads to a forced mate of some sort... The place where I notice it is in engame analysis with EGTBs, where after a long time the PV is scored as Mate in 38 or so, and then it takes a *very* long time to prove the other root moves are worse. A related question: If the score in the hash table is MATE-300 and this would cause a cutoff, shouldn't you cut off even if the draft is not deep enough ?
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