Author: Jeremiah Penery
Date: 16:51:07 01/06/04
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On January 06, 2004 at 18:45:34, Tord Romstad wrote: >On January 06, 2004 at 16:24:07, Robert Hyatt wrote: > >>Yes, but Ferret is not using Hsu's Singular Extension algorithm. not even >>close. Bruce is using a "SE approximation" that works very well, but it is >>not to be confused with what Hsu defined as singular extensions. >> >>I did the full DB implementation in Cray Blitz, and using non-recursive >>null-move R=1, it seemed to work pretty well. I have tried it more than >>once in Crafty, and it simply did not work reasonably whatever I tried. I've >>not decided that it is hopeless, but I have not played with it further in at >>least a couple of years now... > >Have you experimented with Bruce's approximation as well? What were the >results? >I am tempted to try something similar to singular extensions myself some day, >but >I'm afraid I would have to modify the idea a bit to make it work with my MTD(f) >search. > >>I came to the same conclusion that somehow, null-move with bigger R values simply >>doesn't work very well. You extend, but null-move reduces the depth and things get >>lost in the middle. > >That's interesting -- I have precisely the opposite experience. Small R values >have never >worked for me, except in the endgame. He's talking about mixing larger R-value null move with singular extensions, which is more difficult to make work. Crafty normally uses R=2-3 depending on depth.
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