[computer-go] Re: Mogo scalability

[Hideki Kato]

David Fotland: <065201c8adff$2b4a8970$81df9c50$@com>:
>The scalability study showed that mogo gains almost 100 rating points per
>doubling of performance.
>
>But on CGOS, there is mogo 1 CPU and mogo 4 CPU.  I would expect the 4 CPU
>mogo to be 150 rating points or more higher than 1 CPU.  But it is actually
>only 40 points higher.

I'm also wondering this for months.

One reason of this discount is that the MoGo bros running on cgos are 
the _big versions.  By my obserbation (they are running on my pcs and 
both are Q6600/3GHz with different mother boards), mogo_big_4core's 
perallelism is around 300% (by top command), perhaps due to its 
heavier uct part (just my guess).

>I guess this is because in the rating study mogo was mostly playing other
>mogo versions.  A the faster mogo can see everything the weaker mogo sees,
>and more.

I'm not sure.  Mogo_big_4core's winning rate against mogo_big_1core is 
about 60% (1641 / 2743) which corresponds only +70 ELO and current 
rating difference on cgos is about 40, as you wrote.  According to the 
scaling rule of mc playouts, it should be 160 ELO (log2(3) * 100 = 
158.5).

>But against other programs on CGOS, there will be weaknesses common to both
>fast and slow mogo, that other programs might exploit.
>
>Is the true scalability of mogo (against a variety of programs, or against
>people) less than the rating study indicates?

I believe their current ratings on cgos indicate so.

Hideki

>David
>
>
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--
gg at nue.ci.i.u-tokyo.ac.jp (Kato)