[Computer-go] Fwd: [computer-go] Experiments with UCT

[Fuming Wang]

Got it. Thx.

Fuming

On Fri, Dec 31, 2010 at 10:25 PM, Go Fast <fastgo at gmail.com> wrote:

>
>
> ---------- Forwarded message ----------
> From: Rémi Coulom <Remi.Coulom at free.fr>
> Date: Tue, Jul 25, 2006 at 8:22 AM
> Subject: [computer-go] Experiments with UCT
> To: computer-go <computer-go at computer-go.org>
>
>
> Hi,
>
> I mentioned UCT in one of my previous messages to the list:
> http://zaphod.aml.sztaki.hu/papers/ecml06.pdf
>
> I tried it in Crazy Stone. I found that the algorithm described in the
> paper does not work well, but I managed to improve it a lot with a small
> change: I used 1/sqrt(20) instead of 1/sqrt(2) for the C_p constant. It now
> seems to work very well.
>
> Here is a summary of how it works:
>  - Use probability of winning as score, not territory
>  - Use the average outcome as position value
>  - Select the move that maximizes v + sqrt((2*log(t))/(10*n))
>
> v is the value of the move (average outcome, between 0 and 1), n the number
> of simulations of this move, and t the total number of simulations at the
> current position. In case a move has n = 0, it is selected first.
>
> Here are experiment results with Crazy Stone. 170 games are played against
> GNU Go 3.6 at level 10, from 85 different starting positions, alternating
> colors, at various time control (time per game), 1 CPU at 2.2 GHz.
>
>        version 0005  UCT
>  2 min  40%           46.7%
>  4 min  48.2%         56.6%
>  8 min  52.9%         64.7%
> 16 min  57.4%         67.6%
> 32 min  66.6%         71.6%
>
> I have tried hard to improve it, but it seems very difficult. Using a more
> clever backup operator may help, but I have not managed to measure a
> significant difference yet.
>
> I thank Yizao for letting me know about UCT. His program, MoGo, seems to be
> doing very well on CGOS. Maybe Yizao can tell us more about his experiments.
>
> Rémi
>
> _______________________________________________
> computer-go mailing list
> computer-go at computer-go.org
> http://www.computer-go.org/mailman/listinfo/computer-go/
>
>
> _______________________________________________
> Computer-go mailing list
> Computer-go at dvandva.org
> http://dvandva.org/cgi-bin/mailman/listinfo/computer-go
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://computer-go.org/pipermail/computer-go/attachments/20110102/bf8f3e1e/attachment.html>