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Subject: Re: Do hash tables confuse your matefinding routines?

Author: Inmann Werner

Date: 13:28:26 12/27/98

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On December 27, 1998 at 14:59:26, Roberto Waldteufel wrote:

>
>On December 27, 1998 at 14:33:39, Richard A. Fowell (fowell@netcom.com) wrote:
>
>>On December 27, 1998 at 10:34:40, Robert Hyatt wrote:
>>
>>>On December 26, 1998 at 18:51:46, Richard A. Fowell (fowell@netcom.com) wrote:
>>>
>>>>Do hash tables confuse your matefinding routines?
>>>>

>
>I may well be completely wrong, but it might be that the hash tables have a
>single score for "giving mate" and another single score for "being mated". This
>could conceivably cause the sort of behaviour you describe, because the "draft"
>of the hash score will not be taken into account, although the hashed move
>should be good unless it should happen to be erroneous due to repetition or
>50-move rule draws. That would explain why the key move was correct although the
>number of moves to mate would be shorter than it should be. Just a suspicion -
>maybe there is another explanation?
>
>Best wishes,
>Roberto

I think, it is a bug. I had the same one a long time. In hash tables you give in
a score and a distance. If you go back in the tree, the same score is put in to
other positions above. Absolutly correct, but not with mates. And here can occur
errors in calculating the distance to the mate.
Example: mate is 32000, mate in 1 is 31998, mate in 2 is 31996 and so on.
Only a suggestion.

Werner



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