Author: Robert Hyatt
Date: 20:10:12 01/24/00
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On January 24, 2000 at 16:02:48, Ernst A. Heinz wrote: >>Sure, but it did full singular extensions and the rest of the things we were >>all doing then. > >I do not remember having heard or read Hans Berliner talk/publish >about singular extensions in "Hitech". > >Please enlighten me where you got that information from. From sitting across the board from them at an ACM event. Murray was at the table as well, and we had a long discussion about singular extensions after deep though was using them. They implemented them in HiTech very quickly after the idea was published... That was the reason I added them to Cray Blitz... I had used this sort of idea a long while back, at the suggestion of someone whose name I don't recall. It didn't work well in 1978 and I removed them from the program just prior to the ACM event that year, because it costs us well over one ply, and going from 5 to 4 was a killer. They were using them in at least the last few ACM events... I don't recall when they added them. You could probably ask Murray since he probably wrote the code for adding them to HiTech. They were also using Ken's databases in the search (not only at the root) way back then too... > >>I don't use futility pruning now. I am convinced it is too >>risky after fiddling with it for a couple of years. > >Oh, really -- you do not use futility pruning at frontier nodes? No. I did, but found several positions where it simply was at odds with the normal extensions... > >This can actually be made theoretically sound, so where is the >risk? If you lop off one ply, you overlook some tactics. I don't see any way around that at all... I stopped seeing some types of nonsense when I got rid of them, which made the search more stable. > >=Ernst=
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