Author: Matthias Gemuh
Date: 07:15:37 01/15/04
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On January 15, 2004 at 08:06:34, Tord Romstad wrote: >On January 15, 2004 at 07:48:42, Matthias Gemuh wrote: > >>BTW, in QSearch I also generate moves for >> >>1) all passed pawns > >Interesting. I once tried doing this in some endgames (only pawn endgames >and knight endgames, if I recall correctly), but wasn't satisfied with the >results. It's probably worth trying again some time soon. > >>2) all attacked pieces moving to unattacked empty squares > >This sounds a bit too expensive to me. I do something similar, but with >several restrictions. Translated from MTD(f)-lingo to PVS-lingo and >slightly simplified, what I do is roughly this: > >I generate safe moves for hanging pieces if all of the following are >satisfied: > >a) The value of the static eval is >= alpha. > >b) At least two of the pieces for the side to move is hanging. > >c) static_eval-(value of capturing the smallest hanging piece)/4 < alpha > >d) I am in one of the first two plies of the qsearch. > >Always generating all safe moves for all hanging pieces is probably a >waste of time. For instance, if you are a queen up, it is not very >important to find out whether it is possible to save a hanging knight. >And in positions with only one hanging piece, it will usually be safe >to assume that the piece can be saved. Of course there are exceptions, >but I think it is better to ignore them and use the time saved to >search deeper. > >Tord Hi Tord, my approach is even more expensive than you think, as I am talking about attacked pieces, not just hanging ones. I surprisingly get better results at test suites, than with "standard" QSearch. In games, I cannot notice any measurable difference. /Matthias.
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