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Subject: Re: mate threat extension/null move

Author: Bas Hamstra

Date: 06:20:52 09/26/04

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Hi Rick,

What you mention is NOT doing checks, but rather "check-evasions". That way the
qsearch can never see a mate-in-one unless it is a capture. Together with
nullmove that is a real problem which becomes apparent in wac141.

Bas.


On September 25, 2004 at 23:59:27, Rick Bischoff wrote:

>Hi,
>
>I only do checks if a capturing move results in a check, then I just call
>alphabeta with a depth of zero.
>
>>>"found mate" never gets printed out in WAC141 unless I change the null move to a
>>>full width search... Why?  Well, I shouldn't say never, but I let it run to ply
>>>9.
>>
>>Sigh. Do you do checks in quisce? No? If you do recursive R=2 with no checks in
>>the qsearch, nullmove makes the search absolutely BLIND for mates in the last 3
>>plies. Think about it, set the position up with this in mind and analyze it.
>>Further if you use a window <alpha, beta> then you miss a large portion of mate
>>threats anyway.
>>
>>Bas.



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