On Mon, Dec 10, 2007 at 04:08:48PM -0500, Don Dailey wrote: > Would you rather be 95% confident of a win or 90% confident? There is > only 1 correct answer to that question.
Yes, if you can offer me reliable confidence numbers. We all (should) know that MC evaluations suffer from systematic problems that can not just be averaged away statistically. Compare these two positions: playout_benchmark 10000 = Initial board: komi 7.5 A B C D E F G H J 9 . . . . . O O O O 9 8 O O O O O O O O O 8 7 O O O O O O O O O 7 6 O O O O O O O O O 6 5 # # # # # # # # # 5 4 O O O # # # # # # 4 3 O O O O . # # # # 3 2 . O O O . # # # . 2 1 # . O O . # # . # 1 A B C D E F G H J Performance: 10000 playouts 0.032002 seconds 312.481 kpps Black wins = 1937 White wins = 8063 P(black win) = 0.1937 playout_benchmark 10000 = Initial board: komi 7.5 A B C D E F G H J 9 . # . . . O O O O 9 8 O O O O O O O O O 8 7 O O O O O O O O O 7 6 O O O O O O # # # 6 5 # # # # # # # # # 5 4 O O O # # # # # # 4 3 O O O O . # # # # 3 2 . O O O . # # # . 2 1 . . O O . # # . # 1 A B C D E F G H J Performance: 10000 playouts 0.084006 seconds 119.039 kpps Black wins = 7746 White wins = 2254 P(black win) = 0.7746 Which one is better, 77% or 19%? I must admit I don't quite understand the results myself. But they are made with LibEGOs MC, so I trust they show what traditional MC simulation would see. The top group is "obviously" alive but can die in a MC simulation. The bottom group is "obviously" unsettled, so who ever plays there first should win the game. I suppose in some follow-ups, white may be able to live in the resulting space, and win the game that way too. This has nothing to do with the argument of attacking the larger group first, rather the contrary. But it shows that MC evaluations can give results so badly off that there is not always much point in distinguishing between your 80% and 85% confidence. Regards Heikki -- Heikki Levanto "In Murphy We Turst" heikki (at) lsd (dot) dk _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
