Here is a position that exposed some bugs in Pebbles. Maybe it will help you.
1 2 3 4 5 6 7 8 9 A - O - O X - - X - B - X O - O X - O O C - O O - O - X O - D X X X O O O O O O E - O X X X O X O O F - - O X O X X X X G - - X X O O X X - H - O X O - O O X X J - O X O O - X - X X to play. X is already doomed in this position. The bottom O group is in a seki with the X group at right. O cannot play J6 self-atari. X cannot fill in J8 and then play J6, and after X J6, O captures and X cannot recapture. So it will be dual life. Because the top of the board is O's, O have more than half the board, even without komi. The playouts have to handle certain issues well in order to find that. The first point is to filter out plays that make self-atari on large groups. This will cause the rest of the board to fill up until only the seki remains. The the playout will be in a position like the following: 1 2 3 4 5 6 7 8 9 A - O - O O - O O - B O - O - O O - O O C - O O - O - O O - D X X X O O O O O O E - X X X X O X O O F X X - X O X X X X G X - X X O O X X - H X X X O - O O X X J X - X O O - X - X X to play. Pebbles does not detect superko in playouts, so this position will loop forever with J6/J8/J7/pass. In Pebbles, infinite games were scored as draws. I changed that to give the win to O on the basis of its preponderance of material. (No doubt that will bite me at some point.) Even if we detect the superko repetition, it seems to me that we are only getting the right answer by accident. For instance, if X plays J6 then after J8/J7 there is no move for X, so X has self-ataried himself. Another possibility if to see that X's J6 is atari and also self-atari, so X can look for the approach move. In this case X would play J8 instead of J6 which avoids the ko. Then the seki is obvious. How do other programs handle this case? _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
