Author: Jeremiah Penery
Date: 13:03:51 01/17/00
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On January 17, 2000 at 14:01:00, blass uri wrote: >On January 17, 2000 at 12:55:37, Jeremiah Penery wrote: > >>On January 17, 2000 at 06:32:48, blass uri wrote: >> >>>When Deeper blue made his last move in game 2 it did not expect the right >>>Qe3(see IBM logfiles). >>> >>>If I give crafty17.04 a long time it does expect the right Qe3. >>> >>>I know that no micro can find that Qe3 is a draw but some micro can at least >>>understand that Qe3 is the best move for black when deeper blue could not >>>understand it. >>> >>>Crafty is not the only micro that can expect Qe3. >>> >>>It increases the impression of most of the chess players that deeper blue was >>>better in tactics but had not better positional understanding than the >>>microcomputers. >> >>I was thinking about this last night. I'm not sure it is a positional thing. >>My guess is that DB saw that Qe3 led to a long series of checks, but couldn't >>find the quiet moves at that depth to find a draw. Since Qe3 doesn't lead to a >>draw (I.e., DB couldn't see it.), then white can have more attacking chances at >>black's king, because black's queen will be stuck on the other side of the >>board. (In most of the PVs, DB thought Kasparov would trade queens.) >>Of course this is just a guess, but it wouldn't seem completely inconsistent >>with the way DB seemed to evaluate certain things. > >I see it as a positional thing. >I think a good program should at least suspect that it is perpetual check. The problem is that programs can't really think this way. Programs only evaluate based on what the search returns - they cannot generalize and 'suspect' anything. If it searches a very deep checking line and finds that white can escape (because it does not find the quiet move deep in the line), it will evaluate accordingly. I'm sure there are lots of similar positions where it will _not_ end in a perpetual - in these cases, it would be wrong to 'suspect' a perpetual and lower the score. It's a really tough problem to solve. >I think that if both sides have attacking chances it is illogical not to divide >the evaluation by a number bigger than 1 because it is clear that the position >is unclear and if you cannot do it clear by search then the best evaluation is >to admit that you are not sure by using smaller numbers for evaluation. > >I do not know if some of the programs that can expect Qe3 do it but it is clear >that deeper blue's evaluation was illogical. I don't disagree here...
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