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Subject: Re: real job of the qSearch? find quiet vs stop horizon effect

Author: Uri Blass

Date: 08:12:34 08/28/03

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On August 28, 2003 at 10:18:56, scott farrell wrote:

>When you read most literature it says "to find quiet positions" so the eval
>function is more accurate, and the quiescent in the name suggests the same. But
>I think this is wrong, and most people use it for the later.
>
>Here are things I and other have put in/out/in/out of their qSearches:
>- capture by LVA and SEE
>- checks
>- passed pawns
>
>And as we but more into the qSearch, in an effort to stop spending too much
>nodes on it, we try:
>- pruning
>- stand pat - ala Crafty
>- etc
>
>The whole idea of getting to the next ply is to reveals horizon errors and such
>in the current ply.
>
>I have a few positions where a black pawn cant be stopped because of wrong
>colour bishop, and a white pawn similarly close and supported and attacked by
>bothKings and will never score a try. For the main search it just keeps
>horizoning the fact that one pawn is unstoppable. (maybe I need to knowledge for
>this instead of search). As soon as I put passed pawn in qSearch, it sees this
>in about 6 plies, whereas before it needs something like 15 plies (to exhaust
>its best efforts at horizoning it).

I am interested to see an example to see what you talk about.
I guess that you talk about pawn push that are not promotions.

 Checks in the qsearch fall into the same
>pile, whereas captures are different. Extensions dont seem to help the
>horizoning problem, only the qSearch.
>
>So it is the qSearch's job to find quiet or to stop some classes of horizon
>problems?

I think that it is the same.

You are interested in quiet position because otherwise you may have horizon
problems.

Uri



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