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Subject: Re: Aspiration search, PVS

Author: Russell Reagan

Date: 13:34:42 12/28/02

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On December 28, 2002 at 15:34:38, Tony Werten wrote:

>Almost. If the score returns alpha+1, it always means it's better. If this node
>was called itself with (alpha,alpha+1) then there is no score>alpha AND
>score<beta (hence zero window search), so no need to research.

So this means that the range you should test for is (alpha+1, beta)? Does this
mean Bruce's code should be changed to reflect that? Something like:

if ((val > (alpha + 1)) && (val < beta)) // ?

Also, what is meant by alpha+1? I have always assumed that this meant "alpha
plus the value of one pawn." From your words it sounds like alpha + 1 means
alpha + 1 regardless of whether a pawn is worth 1 or 1000.

>Well, not completely. It happens quite often that the report "better move" is
>not correct. At the root, you have to check with an open window to make sure.

What do you mean by "open window"? (-INFINITY, INFINITY)?

Russell



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