Author: James Swafford
Date: 10:07:40 10/17/02
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On October 17, 2002 at 11:32:47, Tim Foden wrote: >On October 17, 2002 at 07:58:00, James Swafford wrote: > >> >>I did this test because I've always heard "35 or 36" as the >>accepted bf when doing a min-max search, and Vincent has been >>claiming that it's more like 40. >> >>Test 1: WAC1-100 (10 sec/mv) ==> avg bf = 34.29 >>Test 2: ECM98 (10 sec/mv) ==> avg bf = 36.85 >> >>So, I'll stick with "35 or 36". >> >>Ok, a few details. No qsearch, no null, no pruning of any kind, > ^^^^^^^^^^^^^^^^^^^^^^ >>no hashing. Alpha was set to -inf and beta to +inf upon entry >>to the search. > >Alpha-beta is a pruning algorithm. If you are using it you should get a bf of >roughly sqrt(36). I assume that in fact you weren't using Alpha-Beta in your >tests either. Yes, I know very well what a-b is. :) I mean no pruning of _any kind_; pure minimax. > >Or do you mean set to -inf..+inf at every search _node_? Yes. This is nothing new of course. I decided to measure full width bf because Vincent was claiming it should be 40. Knuth estimated 38, but 35 is the accepted standard these days. Basically I wanted to see for myself. -- James > >Cheers, Tim. > >>I measure bf after each completed iteration simply by doing: >> bf[iteration] = nodes[iteration] / nodes[iteration-1]; >> >>After each problem, I compute the average of the bf's for each >>completed iteration. After the entire suite, I use the average >>of the averages as the final bf. >> >>-- >>James
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