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Subject: Re: Rybka and CC

Author: William Penn

Date: 06:32:15 02/25/06

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On February 25, 2006 at 01:37:12, Wayne Lowrance wrote:

>CC is my interest in Rybka as published little way back. I run my programs
>against each other in infinate analysis. This takes a lot of time to get a idea
>of performance. What I am asking can anyone tell me of testing where Rybka and
>Fritz8 or 9 compare in, say 2 hours per move as for example.
>
>Thanks much
>Wayne

I haven't heard of any ratings at such long time controls, but it might be
possible with a large number of people cooperating. Maybe it also could be done
wwith a good set of test positions. In the meantime we each try different
engines and then proceed based on instinct.

I don't have Fritz 9 (no DVD player), but have compared the Rybka betas, Fruit
2.2.1, and Shredder 9. I believe Shredder has been left behind. Rybka or Fruit
are better.

Fruit behaves better than Rybka and more predictably at long analysis times,
also produces lengthier analysis outputs. Rybka concatenates the moves to 1 pair
(2 half-moves) after several hours in infinite mode in most positions. Also it
is impossible to predict how long it will take between legs with Rybka. I call
them legs - the successive analysis lines output in the engine window. Fruit's
multiplier for successive legs tends to be about 2, and behaves fairly
predictably. Rybka's multiplier is more like 3, but variable, not easy to
predict; it might be 5 or more. For example you might have let the analysis go
for 2 hours, and wonder how long you'll have to wait til the next one decides to
burp itself out into the real world. With Rybka you might have to wait a long
time, 10-15 hours. With Fruit it's a pretty good bet that the next one will show
up in about 4 hours total run time. These are important considerations for CC
players. I'm sure most CC players understand this kind of thinking, others may
not.

My conclusion at this point is that Rybka is useful at intermediate infinite
analyis times, say 30 minutes to 2 hours. At longer run times it's too
unpredictable and often drives me crazy waiting. So I tend to prefer Fruit if
I'm going to let the analysis run over 2 hours, but I go in cycles. Currently
I'm in an upcycle that favors Rybka, tomorrow it may be Fruit again. Obviously I
don't really know anything, everything is just hunches... :)
WP



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