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Subject: Re: Preprocessor blues?

Author: Ernst Walet

Date: 14:23:18 02/09/00

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On February 09, 2000 at 11:46:35, Ernst Walet wrote:

>On February 08, 2000 at 10:19:06, Stefan Meyer-Kahlen wrote:
>
>>On February 07, 2000 at 16:10:55, Ernst Walet wrote:
>>
>>>I´ve seen some strange evaluation glitch in Shredder 4 with the following
>>>position.
>>>
>>>8/1K6/8/5k2/bR1P1r2/1n6/8/8 w - -
>>>
>>>Shredder wants to play Rxa4, score ply 9-14 about -1.2
>>>
>>>Make the move.
>>>
>>>Shredder wants to play Nxd4, score ply 9-14 about +4.71
>>>
>>>Make the move.
>>>
>>>Shredder wants to play Ra8, score ply 9-14 about -1.3
>>>
>>>
>>>Why such a different score after the first move?  Does Shredder much
>>>preprocessing?
>>>
>>>Ernst-J.
>>
>>
>>Thanks for your interesting post!
>>
>
>
>You´re welcome.
>
>
>>First of all, Shredder's evaluation is always from the point of view
>>of the moving side, so there is "only" a difference of 3.5 pawns and not
>>5 pawns :-)
>>
>
>
>I know, nevertheless....
>
>
>>This is a special case for which I added code after Jakarta 96, where Shredder
>>almost blew a game against Virtual Chess.
>>
>>I, like many other programmers, evaluate a KRN-KR ending very drawish. In your
>
>
>You´re right, this game ended as draw.
>
>
>>second example, I simple deactived that code so Shredder as black this time will
>>go for the last white pawn. If the code were still active, Shredder would never
>>capture the pawn, because KRN-KRP would be better than KRN-KR. I agree that
>>there are other ways to solve that issue, but I haven't touched that code for
>>quite a while now and almost forgot that this is still in there.
>>
>>I agree that this is very brute force, but that method proved to be very
>>succesful in chess :-)
>>
>>Hope this helps
>>   Stefan
>
>Thanks for your reply, Stephan.
>
>Ernst-J.


I´m sorry, not Stephan but Stefan of course!



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