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Subject: Re: Limiting the QSearch

Author: John Scalo

Date: 18:48:35 01/01/98

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>Hi again,

>

>After re-reading your post I think I see a problem with the move

>ordering you use for captures:

>

>  <small takes big>/<equal exchange>/<big takes small>

>

>Try this:

>

>  Always sort the biggest victim first and then in the order of

>  smaller attacker.

>

>This may seem counter-intuitive but it's proven to be quite good.

>

>So QxR should get looked at even before PxB even though PxB is an

>upcapture.  Even though upcaptures seem to be sure winners keep

>in mind that in a quies search lots of really silly positions

>arise.  More often than not the rook in my example is completely

>undefended (often it just moved to some square or was involved

>in a capture itself and is undefended.)  So you would rather

>capture a rook than a bishop wouldn't you?    In the cases where

>the rook is defended the capture search will terminate very

>quickly anyway since the capture of the queen will be the very

>first move tried on the next level.

>

>-- Don



Yep, this improved overall speed by about 20% in "tactical" positions.
Thanks for the tip!



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