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Subject: Re: Slow EGTBs - test position

Author: Dieter Buerssner

Date: 14:32:36 01/16/03

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On January 16, 2003 at 17:03:07, Eugene Nalimov wrote:

>Simplest probable explanation is: you are probing everywhere when you have the
>opportunity. Crafty (and I presume some other programs) probe only first M
>plies. E.g. when they are doing N-ply search from the root position they probe
>only first N*2 plies (or N*3/2, or ... -- you got the idea).

Bob showed a slowdown of 4:1. David showed one of 3:1. Bob has a faster
computer, so one has to assume, that disk accesses will slow down it more. He
has a faster disk, too. So, it seems difficult, to get an conclusion.

Actually, I think 3:1 slowdown is not necessarily bad. 2 years ago, there was a
game Deep Fritz vs. Germany (or the world? I forgot ...). I was interested in
it. It was reaching endgame stage. I was ambitious, to be the first, to show a
mate score. I used your code, I downloaded the very few important 5-men TBs, and
I enabled TB probing in deep qsearch (I was pretty sure, that this will help in
the specific position - but I am unfortuantely not able to give a good algorithm
to decide this). I used only 10 MB hash, 2 MB egtb cache, rest of the little
memory was used for the OS cache. This (on a computer with 56MB RAM, K6-2 475)
gave me a speed of around 10! kn/s. But it was enough to show a mate score much
faster than Deep Fritz :-)

Regards,
Dieter




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