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Subject: Re: Quiescent Explosion

Author: Tom Kerrigan

Date: 00:59:29 06/27/03

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On June 26, 2003 at 22:45:17, macaroni wrote:

>I recently wrote a computer chess program, using alpha-beta, null moving, and
>quiescent search, in the main search function I use a history heuristic to sort
>moves, and that seems to be doing just fine, I can't say the same for my q
>search, the sorting procedure I use for that, is biggest capture, smallest
>attacker. However, when I do a ply 5 search, i get 23,000 standard search nodes,
>which seems acceptable to me, but I get 180,000 q nodes, which seems ridiculous.
>Is this as bad as I think it is? is it expectded? should I just make my Eval,
>MoveGen, MakePosition and UnmakePosition functions faster (if possible)? Also,
>my program manages 75,380 nodes per second, is this high? someone once told me
>that a high node/sec count is not always good.
>Thanks everyone

An 1:8 full-width nodes:quiescent nodes ratio is not unusual if you're just
searching captures and using the move ordering you describe. If you think about
it, it isn't that ridiculous. You have to call qsearch at every leaf node, and
most full-width nodes are leaf nodes, so the smallest ratio you can see is
pretty much 1:2, and from there, if you think about how many captures each leaf
node is likely to have...

-Tom



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