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Subject: Re: Can nullmoves behave like this?

Author: Bas Hamstra

Date: 17:45:40 01/10/01

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The fail high and then low problem is normal if you use nullmove and aspiration
window. Vincent (and me too BTW) doesn't use aspiration window and therefore
doesn't see it. Nullmove causes search inconsistencies.

Bas.

On January 10, 2001 at 06:22:29, Severi Salminen wrote:

>>Did you boundscheck your program already?
>
>No. Can I do it with Visual C++ 6.0 Enterprise?
>
>>Usually weird behaviour in programs where you don't forward
>>prune on alfa (either in qsearch or normal search) nor
>>forward prune in normal search (except for nullmove)
>>is only because of bugs inside the program!
>
>This is what I also fear now...I tried to hunt down a weird bug for 5 hours and
>found out that I had "int History[MAX_PLY][MAX_PLY];"!! And MAX_PLY was set to
>60...No wonder that it behaved little odd sometimes...But how can one find this
>kind of behaviour?
>
>>>>simplest solution is to never give a cutoff from hash if
>>>>it is score 0.00, that's what i do and it always worked.
>>
>>>Sounds reasonable. 0.00 means (or should mean) draw after all :)
>>
>>Oh well 0 or whatever score is your draw score.
>
>Ahem, it was a stupid joke. If eval() return 0.00 you know it is a draw...oh,
>forget it...
>
>Severi



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