On Nov 7, 2006, at 11:10 AM, Magnus Persson wrote:
Quoting Peter Drake <[EMAIL PROTECTED]>:
The probability of winning by starting at b2 is greater than the
probability starting elsewhere, but shouldn't it approach 1.0,
since b2 is a winning move? Do others get this same behavior?
Does anyone have an explanation?
The situation is still such that random play can mess things up.
Even if black
is winning UCT search for white will pick those moves which allows
black to
make bad moves deeper in the tree.
I've had similar experiences with other variants of Monte Carlo Go.
Incidentally, I think this makes ladders particularly difficult.
Thanks, good to know it's not just my program that exhibits this
behavior.
What you should do is to print out the winning percentage for the
principle
variation and not only the top move. In valkyria the winning score
do not
change much at the root but following the tree down a winning
variation often
increase the winning percentage 5-10 % at each ply until it reache
a point
where random play always lead to a win.
It doesn't always work out that way, but sometimes it does:
B2:0.292577
H9:0.291222
C2:0.29693
G2:0.292865
G6:0.312761
B1:0.35
J2:0.666667
PASS
The important thing is that UCT (very!) quickly finds the correct move.
Peter Drake
Assistant Professor of Computer Science
Lewis & Clark College
http://www.lclark.edu/~drake/
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