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Subject: Re: Failing low at the root

Author: Ernst A. Heinz

Date: 01:26:24 08/03/98

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On August 03, 1998 at 04:10:34, Guido Schimmels wrote:
>
>Getting a fail-low at the root is annoying, as we don't know what move to play
>for quite a while.
>There is in article by Schaeffer et al. ("Advances in alpha-beta searching")
>suggesting to restart the search in these cases (setting depth to 1 again),
>exploiting the benefits of a hash-table and finding a new best-move quickly.
>But nobody seems to use this, why ? (or am I wrong here ?).

I believe Aske Plaat introduced the scheme into "CilkChess" (based on
the log files available on their WWW page). Any comments, Don?

The problems I have with the suggestion are (1) that their positive
experience with the scheme stems from checkers where transposition tables
seem to be much more effective in the middle game than in chess and (2) that
it is only a suggestion without any quantitative performance data whatsoever
backing it ... :-(

>An important implementation detail not mentioned in this paper is, how to do >the
>windowing up to the search depth we restarted from - if we do aspiration as
>normal isn't there a danger to get caught in an eternal restarting-loop ?

Add this as another shortcoming of the paper.

=Ernst=



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