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Subject: Re: QSearch question

Author: Robert Hyatt

Date: 16:59:35 08/27/02

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On August 27, 2002 at 18:25:42, Georg v. Zimmermann wrote:

>
>>>In QSearch, if value is >= beta, it returns value without further search.
>>>Is this similar concept to null move in Search()?
>>>
>>>Thank you in advance.
>>
>>Not quite.
>
>Well yes and no. The algorithms both say:
>
>"can I pass now and yet do better than in the main line ?"

Except null-move does a search _before_ making this decision....



>
>The "doing better" is answered by a static eval in q-search and by a shallower
>search in the null move algorithm.
>
>But thats a question of semantics: how similar has something got to be to be
>similar ? :-)
>
>Georg
>
>
>> The idea is this:  If you do a static evaluation and _that_
>>result is >= beta, there is no need to search.  Because you can always
>>stand pat and not play a capture and that is good enough to produce a beta
>>cutoff.  If you try a capture, you can only _raise_ the score, and since it is
>>already good enough to produce a cutoff, there is no point in wasting that
>>time.



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