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Subject: Re: Dr Hyatt: Bugreport?

Author: Robert Hyatt

Date: 10:11:35 10/18/00

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On October 18, 2000 at 10:49:11, Oliver Roese wrote:

>On October 18, 2000 at 10:10:51, Dieter Buerssner wrote:
>
>>I am trying to find a relatively fool proof way, to detect, if
>>an endgame with a rook pawn (or a doubled rook pawn) and the wrong
>>bishop against a lonely king, is a draw. Ideally I would like an
>>algorithm, that only needs the loosing king square (perhaps the
>>winning king square), the pawn square and the side to move, and it
>>should detect, if this is a draw.
>>
>>I tried so far, to only use the pawn square and the losing king
>>square. When the loosing king is closer to the corner, than the
>>pawn, it is a draw. When the distance is the same, the side to move
>>will be better. But this does not allways work. I think, it would be better, to
>>be certain of the draw, and in compilcated cases, that can not be decided, give
>>a small positive score to the bishop side. Have you any ideas about a simple
>>algorithm? Would it be different, when the rook pawn
>>is doubled? And when the losing side has a pawn, that say is not too advanced?
>>
>>One nice example from Tarrasch "Das Schachspiel":
>>
>>[D] 8/4k3/8/7P/4B3/5K2/8/8 w - - 0 1
>>
>>White wins with 1.h6 Kf7 2.Bh7
>>
>Yeah, this is a win after 2..Kf6 Kf4 and white breaks through to g7.
>
>>Which programs, that have knowledge about this sort of endgame will
>>show a winning score without search and TBs? I tried this with
>>Crafty, and it shows a draw score up to depth 6. This is of course
>>problem in this game, because it only takes a fraction of a second
>>to reach depth 7, but it might be dangerous, when the position
>>is reached in the search.
>>
>>Regards,
>>Dieter
>
>Once a while i had a look at craftys sourcecode, and if i recall it correctly
>there is dedicated code to handle this special endgame.
>It might be possible, that you have found an evaluationbug.
>I am currently not at home and have no access to the source code to check this
>out.
>Attract dr hyatts attention to see thats going on here.
>
>Oliver


I will check.  This is probably an exception I don't get...  I want to make
sure that the king can reach the queening square first.  And it ought to handle
this just fine.  But it may well break.  I will certainly look...



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