Author: Robert Hyatt
Date: 19:38:44 01/28/03
Go up one level in this thread
On January 28, 2003 at 15:18:43, Dann Corbit wrote: >On January 28, 2003 at 08:05:57, Omid David Tabibi wrote: > >>As someone mentioned after the game, it is hard to imagine Junior losing in just >>27 moves, had it not used the opening book. Today, the top programs already play >>in a super-Grandmaster level (well, that doesn't include Kasparov of course), so >>why should they blindly play variations played by players weaker than them? >> >>Of course, turning the opening books off totally is not a viable option, as the >>programs still don't have the needed strategic vision to find their way early in >>the opening phase. But maybe a stricter limit (depending on type of opening, >>games played, statistics, etc) should be imposed for choosing moves right out of >>the opening book. > >The problem without book is worse than the problem with book. Steer a program >into the Evans Gambit without a tuned book and a GM will tear it to shreds (for >instance). > >Opening positions are quiet positions where it will take a while for action to >develop. These are among the positions where computers perform the worst. > >Here is a fault which is easily corrected and I am astonished that it has not >been performed. > >A book is a dense object with many, many lines of action. However, compared to >the internal nodes, the exit points from the book are a very small fraction of >the book size. Every commercial book should analyze every single exit position >on a fast machine for ten minutes. Then, there will be no such thing as falling >out of the book and into a bad surprise. > >If any bad positions are found, the engine should backtrack until the position >is no longer bad. > >In other words, we need to check the perimeter of the book. There can still be >internal problems where strategic or tactical moves are missed. But most of the >problems are not like that. It is not as simple as it sounds. We did _exactly_ that in Cray Blitz. Our book had each line followed to the end (while building the book) and then each endpoint got a really deep search added on to it. And it _still_ makes mistakes. We later tried to search every position _along_ a book PV, but all that gets you is even more trouble, because the depth can't possibly be deep enough to understand something like the Evans, for one example... It sounds easy. So does the concept of nuclear fusion. But the implementation details expose +many+ unexpected issues. :)
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