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Subject: Re: Lazy eval and quiescent()

Author: Michael Henderson

Date: 07:18:24 09/07/04

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On September 07, 2004 at 08:34:26, Jeff GAZET wrote:

>Good morning,
>
>i found the following code on this post :
>http://chessprogramming.org/cccsearch/ccc.php?art_id=362206
>
>quiescent()
> {
> if(lazy score + margin < alpha ||
> lazy score - margin > beta)
> score = lazy score modified by margin
> else
> score = eval()
>...
>}
>
>I understand a little, so could someone explain to me those lines ? is it safe ?
>what is the value of "lazy score modified by margin" ?
>
>Regards.

lazy score is a quick eval (maybe just material).  If the lazy score plus
"margin" (maybe max positional score) does not improve alpha, the the coder has
assumed that "standing pat" is useless and does not do a full eval.  (lazy score
- margin) >= beta should be easy to understand.  If your position is great
without playing a move, cutoff.  Lazy score modified by margin is just (lazy
score +/- margin) It's safe to do stuff like this in the qsearch.



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