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Subject: Re: Deep Shredder (2 processors) x Rybka ?

Author: George Sobala

Date: 11:10:35 01/15/06

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On January 15, 2006 at 12:07:50, Robert Hyatt wrote:


>
>There is an easy way to measure this, by heads-up play of a large number of
>games.  I have done this with great frequency in the past, because it helps to
>find bugs in the parallel search if they are there.  My draw-score bug from a
>couple of years back was an example.  I'd play the 4cpu version against a
>single-cpu version using hardware about 3x as fast as one of the 4 cpu
>processors, for a pretty equal performance level.  I was looking for cases where
>the four cpu version saw draws that the one cpu version did not, or vice-versa.
>Match results were pretty equal once the draw score bug was found.  Initially
>the single-cpu program had a slight edge over the other, but then the SMP
>program was overlooking draws when it should have won, and let the single-cpu
>program escape with a draw.  The single-cpu program won the games it should have
>won since it didn't stumble into a draw by error.  Once that was fixed, things
>seemed to be pretty equal as expected.
>

Real data! - interesting. Thanks.



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