Author: Robert Hyatt
Date: 19:44:49 01/06/04
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On January 06, 2004 at 19:51:07, Jeremiah Penery wrote: >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. Correct. I think I originally misunderstood his question when I first responded a few minutes ago to the post you are responding to.
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