Author: Uri Blass
Date: 09:48:32 01/20/03
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On January 20, 2003 at 12:11:07, Jon Dart wrote: >On January 20, 2003 at 00:15:31, Scott Gasch wrote: > >>Hi all, >> >>I'm pondering a major code overhaul of the engine to implement some ideas I've >>been thinking about for a while. One of these is attack tables. So I wanted to >>seek the advice of those of you who have attack tables in your engines already. >> >>First, I assume attack tables are things you want to do incrementally. This >>seems really expensive though > >Arasan used to have incrementally updated attack information. If I remember >right, it was lazy about it and didn't deal with stacked attackers, so the >attack info was not really useful for SEE. Now it uses rotated bitboards and can >do an accurate SEE. > >Generally, I now think that you want to do as little as possible in your "make >move" routine. The faster your h/w is, and the deeper you go, the more cost you >are paying if you are loading things into "MakeMove" and "UndoMove". Of course >doing this can make your eval faster, but then some of the nodes you are moving >to won't even be evaluated because of pruning, etc. Overall incremental attack >generation cost Arasan speed, and taking it out was an improvement. Of course, >your mileage may vary. > >My overall impression from reading Ed's stuff is that many of his techniques >work well together in his program but are not readily usable in a more >conventional program. Rebel has traded speed for reduced tree size. It is a very >interesting approach and evidently works well, but most programs are tuned to go >as fast as possible. > >--Jon I doubt it. Are most programs faster than Rebel in nps? If you think about top programs then the question is the following: Are Shredder or Hiarcs or chessmaster faster than Rebel? If you think about the weak program than the question is if tscp is faster than Rebel in nps. If you think about average programs then Movei or Butcher are not faster than Rebel in nps. There are a lot of example for programs that are not tuned to run as fast as possible and in a lot of cases the program could run twice faster but the programmers were too lazy or did not know or did not want to do it. Uri
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