On Mon, Oct 18, 2010 at 07:18:51PM -0700, James Pettit wrote:
> I have a basic UCT bot with AMAF/RAVE implemented as part of my master's
> research. The bot can muster a small win-rate versus Gnugo level 6 (~20% as
> black), but usually loses games by not forming 2 eyes and being completely
> captured. I have uniform random playouts, with simple ko and self-eye moves
> disallowed. Is this normal for a basic UCT bot? From looking at territory
> visualizations (the viz. post has been most interesting), the bot seems to
> want to capture white groups that can usually be kept alive, and ignores
> forming eyes to keep itself alive. I'm wondering if I messed up somewhere in
> the tree portion searching possible opponent moves. Any thoughts?
You are likely to have some bugs in there. Accidentally reversing
black/white in the minimax, starting the playout with the opposite color
than I should, counting the result wrongly, typos in tree descent
equations, updating wrong tree nodes, bugs in eye detection, suicide
mishandling, etc. etc., been there, done all that. :-)
Trace through all your code - both tree part and playout part and
carefully verify that it all makes sense; that the tree is growing along
sensible sequences, all moves are made properly, colors are alternating
properly, simulations go through correctly and end in sensible
positions, the tree values are updated properly. Debugging UCT programs
is lenghty and frustrating.
Note that from my experience, AMAF/RAVE is only very marginally useful
(or not at all) with uniform random playouts, and only starts to be
effective when you add 3x3 patterns and basic capture heuristics.
Perhaps try using raw UCB1 for starters and getting that work properly.
Then, try out your program on CGOS and check the rating against
comparable implementations:
http://senseis.xmp.net/?CGOSBasicUCTBots
If it's roughly in line (you need to wait for few hundreds of games for
the rating to converge reasonably), you can be sure that you have
something that's reasonably bug-free and work from there.
--
Petr "Pasky" Baudis
The true meaning of life is to plant a tree under whose shade
you will never sit.
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