Many Faces reads ladders in both the tree and the play outs. In play-outs we already had a rule "don't play self atari (with many exceptions)". A similar rule is "don't play a move that is captured in a ladder (with many exceptions)". The moves that play out the ladder are not made in the play-out itself, but ladders are evaluated as mart of the play-out move generation policy. Once you have heavy play-outs, the overhead of reading ladders is not very high.
In the tree portion, I use the Many faces of Go engine to bias moves, and it does tactical local search for up to 3 liberties, not just simple ladders. David From: [email protected] [mailto:[email protected]] On Behalf Of Don Dailey Sent: Tuesday, May 14, 2013 8:51 AM To: [email protected] Subject: Re: [Computer-go] ladder I was curious about this myself. I am so heavily involved in computer chess that I'm having trouble keeping up with Go. But I am amazed at how strong the 19x19 go programs when I know that ladders are a big part of go and that they are not easily dealt with in playouts. So if I understand this correctly, you do significant analysis in the tree portion of MFGO but not in the playouts? Is that pretty typical of the best programs? Don On Tue, May 14, 2013 at 11:41 AM, David Fotland <[email protected]> wrote: I'm not sure I understand exactly what you are asking, but I think neither is true. Many MCTS programs read ladders as part of move generation or bias. For example ladder status may be part of the pattern data used for move bias in the UCT tree. During play outs, some programs use ladder status to select the move to play. For example a local response to the last move might be "If the last move put a stone in atari, play in the liberty of the stone in atari, provided it is not captured in a ladder". Many Faces uses ladder status in these ways. I don't think a program should play out the ladder in the play out, since half the moves are very bad. David From: [email protected] [mailto:[email protected]] On Behalf Of Chun Sun Sent: Tuesday, May 14, 2013 7:22 AM To: [email protected] Subject: [Computer-go] ladder Hi... do MCTS programs usually put a specific ladder branch, or this branch should be automatically generated given the right implementation? This question has been hoovering in my head for a while and I wanted to take the shortcut to ask here :) Thanks, Chun _______________________________________________ Computer-go mailing list [email protected] http://dvandva.org/cgi-bin/mailman/listinfo/computer-go
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