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Subject: Re: Computer chess schools of thought

Author: Sune Fischer

Date: 05:57:20 07/01/02

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On July 01, 2002 at 07:50:12, Richard Pijl wrote:

>On July 01, 2002 at 07:18:45, Sune Fischer wrote:
>
>>On July 01, 2002 at 07:07:10, Richard Pijl wrote:
>>
>>>On July 01, 2002 at 06:50:51, Sune Fischer wrote:
>>>
>>>>On July 01, 2002 at 06:34:31, Richard Pijl wrote:
>>>>
>>>>>>I presume the reason for this is the slow InCheck implementation, so the idea is
>>>>>>to call the heavy functions as little as possible.
>>>>>
>>>>>And search less nodes as you do not have to search the check evasions. I think
>>>>>that is the real winner.
>>>>
>>>>Oh well I don't do that in qsearch. It just means that I might evaluate a
>>>>position where the king is in check, but that's still better than to evaluate a
>>>>position where the king has been captured, IMHO. :)
>>>>
>>>
>>>In that case you could just assign a very high material value to a king, so you
>>>can determine a captured king by the material balance and skip evaluation with a
>>>fail low ... Then you have no need for calling InCheck in qsearch at all
>>
>>But my InCheck is fast (at the expense of slow make-/unmakemove), so it's no
>>problem for me.
>>And I don't see how it solves Craftys problem, you still might evaluate
>>positions where the king is in check.
>
>Yes, but if you're not doing check evasions in qsearch, it doesn't matter, does
>it?

I misunderstood, I thought the idea of check evasions in qsearch was _not_ to
evaluate while in check, since technically it cannot be considered a quite
position.

>>Example, your are in check (but don't know this since you don't detect it) and
>>you have no captures so you evaluate and return alpha.
>>
>>It could also happen that both kings get captured in qsearch, since kings have
>>the same value their scores will cancel and the evaluation score will look
>>normal.
>
>If you're evaluating on every move in qsearch that cannot happen as you will
>return failing low on the first king captured.

Right :)

>>-S.
>>
>Richard.



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