[Computer-go] Congratulations to Many Faces of Go!

Erik van der Werf erikvanderwerf at gmail.com
Tue Mar 9 02:11:37 PST 2010


Steenvreter also uses upper confidence bounds.

Erik

On Tue, Mar 9, 2010 at 6:46 AM, David Fotland <fotland at smart-games.com> wrote:
> Many Faces still uses UCT to control exploration.
>
> David
>
>> -----Original Message-----
>> From: computer-go-bounces at dvandva.org [mailto:computer-go-
>> bounces at dvandva.org] On Behalf Of Petr Baudis
>> Sent: Monday, March 08, 2010 12:30 PM
>> To: Nick Wedd
>> Cc: computer-go
>> Subject: Re: [Computer-go] Congratulations to Many Faces of Go!
>>
>> On Mon, Mar 08, 2010 at 04:43:29PM +0000, Nick Wedd wrote:
>> > Congratulations to Many Faces of Go, the undefeated winner of
>> > yesterday's KGS bot tournament.
>> >
>> > My report is at http://www.weddslist.com/kgs/past/57/index.html
>> > I hope you will report any errors, as usual.
>>
>>   Thank you for the report!
>>
>>   On the hardware - Puego was r1098, still run on the i7 920, but this
>> time with 8 threads instead of 4. CzechBot was still run on the same
>> hardware. pachi2 was AFAIK running on 21 cores, but probably not of
>> three Mac Pro machines - I hope Jean-Loup will be able to fill on the
>> details.
>>
>>   I beg to disagree with the analysis of the pachi2-ManyFaces1 game.
>> I think that the move at 177 was neccessary, there does not seem to be
>> alternative for white to live with its roup. Also, pachi2 kept being
>> very optimistic for the rest of the game and I also had the feeling
>> that the game looks favorable for white (though I did not count).
>> It seems to me that the blunder was only at the D19 move (267);
>> leaving the ko seems to be too dangerous and the bottom corner is not
>> enough compensation, especially given black's nasty followups. IMHO
>> the bot did not read the E19 ko correctly; I do not have detailed
>> winrate logs (yet?), though.
>>
>>   Thank you for the praise of Pachi. :-) I'm sorry I confused you
>> on KGS previously, the bug was not in the codebase that was used
>> in the tournament. It does seem our flaw indeed is time management,
>> though in normal byoyomi games its clever implementation by jlg
>> boosts the strength - the problem seems to be poor handling of S.D.
>> and S.D.-like settings, probably due to faulty changes of mine.
>>
>>   The surprise of the tournament for me was the excellent stv's
>> performance, looks like Steenvreter is to be reckoned with - I wonder
>> if its author plans to divulge more details on its internal operation.
>>
>>   Finally, a general note on the UCT idea conclusion - I would say that
>> while the UCT is evolutionary at the beginning of current bots, the
>> current RAVE-based MCTS algorithm actually has nothing to do with UCT
>> anymore since the upper confidence bounds are not used anymore - the
>> RAVE information fully substitutes them as online exploration bias.
>> Perhaps "RAVET" instead of "UCT".  ;-)
>>
>>   P.S.: I wish I would name Pachi's key component 'mcts' instead of
>> 'uct' now. :-)
>>
>> --
>>                               Petr "Pasky" Baudis
>> http://pasky.or.cz/ | "Ars longa, vita brevis." -- Hippocrates
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