Author: Graham Laight
Date: 10:49:28 05/02/01
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On May 02, 2001 at 11:33:40, Robert Hyatt wrote: >On May 01, 2001 at 18:21:08, Graham Laight wrote: > >> >> >>This represents a major flaw in modern chess programs with their relatively >>simple eval functions. >> >>They have to accurately evaluate up to a million NPS (single processor). This >>represents a node every 1000 clock cycles - and this can ONLY be done in a >>relatively simple way. In many positions, the quick eval is enough - but in many >>other positions - it just isn't. Sometimes, you'll get lucky and get the right >>eval for the wrong reasons. Other times, you'll have the reasons roughly correct >>- and still deliver the wrong eval. > > >This is not quite accurate. In the case of Crafty, it will do about 1/2 >million nodes per second on a 1ghz processor. That 1ghz processor executes >2 or 3 instructions per clock cycle. In Crafty's case, the instructions per >node turns into more like 4000-6000, rather than 1000. When you factor in the >unique way bitboards can answer evaluation questions (ie is this pawn passed >takes 1 operation) this turns into closer to 10,000 instructions per node... This is true in Crafty's case, but at WMCCC last year, some programs were getting over 900,000 NPS on processors which were little more than 1 Ghz. >Also, I don't think today's evaluations are "simple". I'm a pretty decent >chess player and there is very little that I know that Crafty doesn't, in terms >of general chess knowledge about evaluating positions. There are some things I >know based on experience that are hard to code of course... but general >positional skills are not bad. This is relative. If computer evaluations were as good as human ones, the humans would necessarily lose, since they don't evaluate as quickly as computers. >> >>As for getting "every positional factor in the position", as you've said above - >>I think we're talking new technology. Something better than a top human, I >>think. >> >>I believe it would be possible, with today's technology, to set up a system that >>could, somehow, automatically tease out the major positional factors from every >>position in the Chessbase database. This would make for a superb chess position >>evaluator. >> >>-g > > >I don't think this is possible, until a human can do it himself... I think it would be possible. Maybe by using some combination of data mining, generating mathematical representations of patterns, using neural networks, and using genetic algorthms to evolve patterns and weightings, it could be done. Once trained, I'm sure the computer could then get through the database faster (and more accurately) than humans. -g
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