Many Faces recognizes simple sekis in playouts. It's pretty important to play well, since a lot of corner situations end in seki (when played poorly by the playouts).
> -----Original Message----- > From: computer-go-boun...@computer-go.org [mailto:computer-go- > boun...@computer-go.org] On Behalf Of Jason House > Sent: Tuesday, June 30, 2009 10:25 AM > To: computer-go > Subject: Re: [computer-go] Complicated seki with Ko > > Is it possible to explicitly use a monospace font? I can't read your > board positions. > > I haven't heard of any handling of seki in playouts except for Remi's > CrazyStone. I don't think he's ever given specifics on how he did it. > Maybe he'll respond to your e-mail? > > Sent from my iPhone > > On Jun 26, 2009, at 1:37 PM, "Brian Sheppard" <sheppar...@aol.com> > wrote: > > > 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/ > _______________________________________________ > computer-go mailing list > computer-go@computer-go.org > http://www.computer-go.org/mailman/listinfo/computer-go/ _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
