Author: Dann Corbit
Date: 20:52:45 01/28/03
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On January 28, 2003 at 22:38:44, Robert Hyatt wrote: >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. :) Well, that is true. But you can discover the openings your program does not understand. Then you can get out a book like NCO and figure out what's what. But (as you say) the devil is in the details.
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