I'd like to give here an example to make things clear. The conditions are: 1) Using digitizing scheme that maps real score to [0,1] (or [-1,1]) so that the program cannot distinguish losing/winning by 0.5 or 10.5 pt at all. 2) Playouts include some foolish moves (usually with low but not zero probability), not to connect large groups in atari position for example, due to hold its randomness. 3) The position is at early endgame where there are no moves that gain greater than 2 pt, for example, in perfect play. 4) Black is behind by 0.5 pt.
The playouts may return winning but gambling move (perhaps with low probability) under above conditions, especialy in case of the number of playouts is small which is usually true on 19x19, and UCT will choose it. The question is, which is better to keep 0.5 pt behind or to play gambling moves (here I mean such moves that B will lose many pts if W will answer correctly) with expecting W's (stupid) mistakes? In addition to above, there is one more issue to consider. If the playout has a systematic error, nakade for example, it's not good to keep 0.5 pt ahead. Having more margin is clearly better. The idea of floating komi helps above two. I'd like to emphasize that I know it's not a universal solution. As it seems, however, very hard to solve nakade problem, it could be a pracitical solution. -Hideki -- [EMAIL PROTECTED] (Kato) _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
