The only think I can suggest which perhaps hasn't been tried is to
only consider the score in the evaluation if NONE of the playouts
resulted in a loss.


On 2/7/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:

     It's a *weighted* average of all moves. UCT tree search doesn't explore
"bad" moves as often as good ones, so they don't contribute as much to the
estimation of the worth of a node.

- Dave Hillis


 -----Original Message-----
 From: [EMAIL PROTECTED]
 To: computer-go@computer-go.org
 Sent: Wed, 7 Feb 2007 4:31 PM
 Subject: Re: [computer-go] MC approach



That drives me nuts! Minimax search would eliminate bad lines of play
whenever a refutation is found. A good opponent would not play badly, and
the quantity of possible bad moves should not affect the evaluation of good
moves - but that seems to be what MC does, averaging out all moves
regardless of whether they are known to be good,  have been refuted, or are
of indeterminate status.

 What am I missing?

  Terry McIntyre




----- Original Message ----
 From: Nick Apperson <[EMAIL PROTECTED]>

 If it only did one playout you would be right, but imagine the following
cases:

 case 1: White wins by .5 x 100, Black wins by .5 x 100
 case 2: White wins by 100.5 x 91, Black wins by .5 x 109

 the method that takes into account score would prefer the second case even
though it has a lower winning percentage that may be represented by the fact
that white is making an overplay for instance.  Obviously this is just one
example, but there are many cases like this and overplays tend to be
priveledged in a sense I would suspect with this kind of algorithm.

 - Nick


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