If you maintain a list of "strings" ( connected groups ) of stones and their liberty counts - or perhaps the actual liberties - it should be fairly quick to find a string with just one liberty. In any case, if I read the explanation correctly, this happens infrequently, if several less-expensive tests fail; the cost would be amortized over many trials.
Terry McIntyre <terrymcint...@yahoo.com> "And one sad servitude alike denotes The slave that labours and the slave that votes" -- Peter Pindar ________________________________ From: Peter Drake <dr...@lclark.edu> To: Computer Go <computer-go@computer-go.org> Sent: Monday, August 31, 2009 9:56:16 PM Subject: [computer-go] MoGo policy: capture stones anywhere? MoGo's playout policy (at one time) is given in section 3.2 of Gelly et al's paper, "Modification of UCT with Patterns in Monte-Carlo Go": "We describe briefly how the improved random mode generates moves. It first verifies whether the last played move is an Atari; if yes, and if the stones under Atari can be saved (in the sense that it can be saved by capturing stones or increasing liberties), it chooses one saving move randomly; otherwise it looks for interesting moves in the 8 positions around the last played move and plays one randomly if there is any; otherwise it looks for the moves capturing stones on the Go board, plays one if there is any. At last, if still no move is found, it plays one move randomly on the Go board." We've implemented much of this, which has made Orego considerably stronger. The problem is with this part: "otherwise it looks for the moves capturing stones on the Go board" Does this really mean traversing the entire board looking for captures? Doing so seems to create a catastrophic speed hit. Peter Drake http://www.lclark.edu/~drake/ _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
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