Author: Robert Hyatt
Date: 05:15:24 01/20/00
Go up one level in this thread
On January 20, 2000 at 02:18:51, Ed Schröder wrote: >On January 19, 2000 at 18:55:42, Dann Corbit wrote: > >>On January 19, 2000 at 18:34:52, blass uri wrote: >>[snip] >>>The question is if the move of deeper blue was the right move. >>>It is not clear that 36.axb5 was the right move. > >>So the argument against 36.axb5 was that it is not such a good move? >>Every program has bugs. There are a very large number of tunable parameters >>with the deep blue machine. Perhaps one (or many) of them was not optimal. > >You misunderstand. It's the DB main-line for 36.axb5 what made Kasparov >suspicious. In this main-line DB sacrificed 3 pawns for no direct win >but for a dangerous looking king attack, all very human-like. Kasparov >could not believe his eyes (he still can't) and started the accusation >human intervertion took place as he could not believe a computer was >able to produce such a (super) main-line. > >So this whole issue is NOT about the move 36.axb5 but about the asthonising >main-line DB produced. > >Ed > Not quite. At the time of the accusation, Kasparov had _no idea_ what the PV from DB was. He wanted to see it. He had not. It was just a 'feeling' at that point. It's rubbish now... > > >>>If it is not the right move then the expression solve for finding axb5 is not >>>the right expression. >>> >>>It is possible that it found this move because of a bug because I saw no tree >>>that prove to computers that axb5 is the right move. >>There are lots of moves that computers cannot verify. They cannot verify the >>NOLOT positions, for instance. If we saw the output of Deep Blue on the NOLOT >>positions and did not have SuperGM analysis already available, a lot of us would >>think the analysis was wrong or there might be a bug. >> >>>The case with the nolot positions is different because I think that there is a >>>tree to prove the solutions(it is easy for programs to see that playing moves >>>not in the tree is bad). >>I don't believe in any tree to prove solutions unless it leads to checkmate. A >>deeper analysis can always reveal a better move. Indeed, the analysis for the >>"... Goes Deep" articles in the computer chess journal shows that there is about >>a 17% chance of improvement for each new ply. That means that the odds that we >>keep the current selection is (1-0.17) = 0.83. So after two plies, the odds are >>.83*.83 = 0.6889, after 3 plies it is 0.571787. After ten more plies it is >>0.1551604118721 or only about 16% chance that we keep the same move. >> >>A five year old looks at a chess board. He sees that he can take the pawn. His >>big brother set up a trap to take the bishop. But his dad is watching and sees >>a forced mate and kibitzes (he feels sorry for the 5 year old). >> >>As we move up the ladder, the more deeply we see, the better our choices. I >>don't think it will ever stop getting better until you can see all the way to >>checkmate. >> >>In other words, all analysis is tenative. Unless it leads directly to forced >>checkmate.
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