Author: Robert Hyatt
Date: 06:49:07 09/08/99
Go up one level in this thread
On September 07, 1999 at 22:52:10, William Bryant wrote:
>I was reviewing my code, and noted in the root search when the score obtained
>is > alpha (and < beta) I was doing the following:
>
>alpha = score;
>beta = alpha + WindowSize;
>
>I thought this idea came from Crafty, but now I can't find it in the Crafty
>source. Further, although it makes the initial ply's slightly slower, it speeds
>up the search overall and improves the LCTII score as well.
>
It is in SearchRoot(). I do it because after I fail high at the root, and
get a score, I don't want to continue searching root moves with beta=+infinity
as that can slow you down if the position is wild.
>Question:
> Is there any harm in updating beta to the aspiration window size at the root
>when a score is backed up to the root and alpha is changed?
>
> Is this idea good, bad, neither?
>
> Did this come from Crafty at one point?
It had better still be in there. :) Although I can't guarantee that it was
not removed for a version or two for testing something else. In the current
SearchRoot() (searchr.c) I find this at line 150:
alpha=value;
beta=value+40;
root_beta=beta;
>
>Thanks.
>
>William
>wbryant@ix.netcom.com
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