[computer-go] New version of Crazy Stone

[Rémi Coulom]

Hi,

I have just come back from the Turin Computer Game Olympiad. I enjoyed 
this event very much. It was great to meet all the programmers. The 
version of Crazy Stone that participated in the tournament, and the 
games that it played, are now available for download:
http://remi.coulom.free.fr/CrazyStone/
The site of the Olympiad is there:
http://www.cs.unimaas.nl/olympiad2006/index.htm

Main changes in Crazy Stone are multiprocessor support, and expected 
territory replaced by probability of winning. Using the probability of 
winning increased the strength of Crazy Stone tremendously. By changing 
one line of code, Crazy Stone improved from scoring 35% against GNU Go 
to more than 60%. After more fine-tuning of the search parameters, it is 
now even stronger.

Up to 4 processors, the speed seems to scale rather well. In case any of 
you has a machine with more than 4 CPUs, I'd be very curious to know the 
   speed you get. In order to measure it, run the ::MCSearch::Benchmark 
Analyze command (in gogui) with different values of the "Processors" 
parameter in ::MCSearch::Parameters. I found that it is possible to get 
a small speed increase on Intel processors with hyperthreading by 
setting the number of processors to 2 (I get about 30% speedup on my P4 
3.4GHz).

I will let Crazy Stone play on CGOS with the 4-CPU machine for some time.

Greetings,

Rémi