Author: Bas Hamstra
Date: 01:41:50 10/12/00
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On October 11, 2000 at 07:43:58, Dan Newman wrote: >On October 10, 2000 at 12:16:33, Steve Maughan wrote: > >>Dan, >> >>Your hash hit rate is way higher than mine (only 4.4%). I'm using a two hash >>table system with a depth based store criterial and an always replace criteria. >>What the general consensus - is this too simplistic? Is a multiple hit >>attempts algorithm much better? >> > >That's what I'm using (the two level table). I believe Vincent has said that >he uses a multiple hit scheme to good effect. I've always worried a bit about >the memory traffic though, but if you don't probe in the qsearch, it turns out >(at least in my case) to not be very bad at all. (I only got a small change >of a few percent in node rate when going from a 100 MHz to 133 MHz memory >clock. And the node rate scales almost linearly with processor speed up to >933 MHz.) I may try multiple re-hashing some day, but it's a low priority >since the two-level seems to work so well... > >>My first move cutoff ratio is also poor at 85%. I assume the two are linked! I wouldnt suspect so. In my case the system of hashing doesn't seem to matter a lot. I tried 8 probes, 4 probes and Crafty's system. No big differences there. I tried to prove that Crafy's system did better at extreme depths, but even there it doesn't matter a lot. As for the cutfirst rate, I do over 93% average on WAC. But for example in the startposition I see 88% or so. I don't see how your hashing system would affect this much. (Since way you hash don't seem to matter a lot, it is probably reasonable to choose for speed, like Bob did) Bas Hamstra.
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