On Wed, 2008-12-10 at 18:56 +0000, tony tang wrote: > Hi guys, > > It would be interesting to know how everyone limits the number of > possible moves at the > beginning of the game. Assuming the board is 19x19 with no handicap > and black placed a stone, > that leaves (in theory) 390 possible positions which translates to 390 > children from the root (empty board). > With my understanding of UCT it appears that all 390 positions have to > be simulated numerous times > and the node with the highest winrate gets explored further. *please > correct me if im wrong* > > Do most people limit their play in corners and sides, if so how? > Pruning entire branches at this stage would > be a bad idea due to well documented reasons, but i have heard pruning > being employed at this stage, if > so what algorithms are used to smartly prune.
Some of my programs do not place any stone on the edge, unless it touches some other stone. I also count the diagonal, so if there is a stone diagonally next to an edge point, I allow a move to that point. But if there is nothing diagonally or orthogonally adjacent, I do not allow a move to that point. This is not a perfect rule. But a modification might be to not allow any move on the edge if there is a stone of either color within Manhattan distance 2 or 3 or so. Of course if you use patterns, you can start to get much more specific and consider exceptions to this rule. I think with some creativity you can produce other kinds of rules that can at least limit the choices for the first several moves. I'm too weak to know how to construct these rules. If you have a large enough database of strong master games, you might be able to construct some rules and use the database to verify that your rules are good. It could be based on building a hypothesis, then testing to see if your hypothesis holds. One must be very careful how to interpret things - because if there are 350 possible moves, the hit rate must be extremely high. So if your test rule is to prohibit one of these 350 moves, then 1 hit out of 350 is probably way too many because that is what we would expect from any "average" move. You want to find rules to discard moves that are close to certainty not the best move. - Don > > Thanks, > > Please link me to the thread if this has already been discussed. > > > ______________________________________________________________________ > Get Windows Live Messenger on your Mobile. Click Here! > _______________________________________________ > computer-go mailing list > [email protected] > http://www.computer-go.org/mailman/listinfo/computer-go/
signature.asc
Description: This is a digitally signed message part
_______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
