Author: Sune Fischer
Date: 00:16:40 07/21/02
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On July 20, 2002 at 22:22:22, Robert Hyatt wrote: >On July 20, 2002 at 08:13:44, Gian-Carlo Pascutto wrote: > >>On July 20, 2002 at 08:04:01, Sune Fischer wrote: >> >>>I think it matters "a factor of 2". >>> >>>1) it helps you to prune >>>2) you get better evaluation in the upper plies when you can return a score >>>based on a deeper search. >>> >>>number one will show itself directly because you iterate deeper, the second one >>>you don't "see", but it does improve depth along some branches in the same way. >> >>1) I get +- 10% hash hits (and less prunes) in typical middlegame. Not enough to >>matter a factor of two (but I didnt check this so not 100% sure). >> >>2) Uh? >> >>-- >>GCP > > >Run your program with a tiny hash and a deep search. Then a big hash and >a deep search. In middlegame positions this will be at least a factor of >2x. Measure time to depth. Small hash might take 4 minutes to get to depth >12, then big hash will take around 2 minutes... You shouldn't measure time to ply, that would not give you the full benefit of the hash. You should use time to find the right move. I have never seen the hash bring only a factor of 2, even in middlegame. Last I tested I saw a mate in 5 being solved in 1/4 of the nodes with the hash. Some things are also spotted a ply sooner because of the hash, so time to ply wouldn't be the right way to estimate the value of the hash. -S. >I posted a bunch of this kind of analysis a few years ago when prompted by >Komputer Korner (Alan Tomalty).
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