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Subject: Re: Correct values if all moves are pruned?

Author: Severi Salminen

Date: 00:52:18 01/06/01

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On January 05, 2001 at 17:20:09, Bas Hamstra wrote:

>In such a situation you assume that that are no good captures. So you return the
>score of the evaluation for that node IF it is above Alpha. Otherwise just
>Alpha.

You mean the 2. case? I think that if all captures are pruned and standpat score
is <alpha I should return that instead of alpha. My point for this was that
returning something lower than alpha might improve all the researches. I just
didn't know how much lower value I could safely return.

>>Hi!
>>
>>1.If I prune a move in normal search: if(material+gain(move)+FMARGIN<=alpha)
>>what should I assign to the best score so far? Material+gain, material+FMARGIN,
>>material+gain+FMARGIN or material only? Now I'm using material+FMARGIN but it
>>can't be right. Material+gain sounds right because that would be returned from
>>qsearch if stand pat fails high?
>>
>>2.I'm using now SEE and I wonder what is the "correct" value to return from
>>qsearch if I prune all captures: if(eval()+seescore(move)+MARGIN<=alpha)? Now I
>>just return alpha. If all moves result a score<=alpha should I return
>>eval+seescore or something else.
>>
>>I ask this because PVS or aspiration window search doesn't seem to like "wrong
>>values"
>>
>>Severi



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