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Subject: Re: a position when crafty is better than deeper blue

Author: Robert Hyatt

Date: 11:36:38 01/18/00

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On January 18, 2000 at 10:58:30, blass uri wrote:

>On January 18, 2000 at 10:05:21, Robert Hyatt wrote:
>
>>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.
>>>
>>>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.
>>>
>>>Uri
>>
>>
>>I don't agree there.  Computers have _always_ played "inhumanly".  I can recall
>>hundreds of games (mostly crafty, but also Cray Blitz and even Deep Blue) where
>>a program will follow a line that appears to win quicker, but which leaves the
>>program dead lost if it makes _one_ mistake.  Where a human would follow the
>>path of a sure (but longer) win, while leaving a lot more room for mistakes.
>
>I do not say that programs should never follow a line which leaves the program
>dead lost if it makes one mistake if they have a sure(but longer) win.
>
>I said that it should by the evaluation function see that both sides have
>attacks after Qe3 in game 2 so the evaluation should be closer to draw.
>
>Uri


That is hard to do.  I have 'plans' to do something about this, as it is too
easy to get to a pawn-up endgame with queens still on (and no other pieces)
which tends to lead to a draw with all the checks...  The fewer the pawns,
the easier...



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