I'm not sure whether they meant different things when they were first coined, but maybe that doesn't matter, and there are two different approaches that should be distinguished somehow.
When a node has been visited the required number of times: 1) Use patterns, heuristics, ownership maps from the earlier playouts through it, etc. to calculate a score for each move. Then rank them from prettier to uglier. At this node, only allow moves within the top N prettiest moves, where N grows slowly with the number of subsequent playouts through the node. 2) Calculate the score, as in 1). Initialize the win/loss record for each move *as if* many more "prior" playouts had already gone through this node. Prettier moves are initialized as if they had a higher proportion of prior?wins. Typically, it is the win/loss record for RAVE moves that gets this prior adjustment. They can be combined too. If the calculations involved?are expensive, then it is important to hold off until several playouts have gone through the node. Most nodes don't get visited more than once or twice.?If they use something like ownership maps, then, naturally, one has to wait until some data has been gathered. - Dave Hillis > -----Original Message----- > From: computer-go-boun...@computer-go.org [mailto:computer-go- > boun...@computer-go.org] On Behalf Of Petr Baudis > Sent: Tuesday, September 29, 2009 7:07 AM > To: computer-go@computer-go.org > Subject: [computer-go] Progressive widening vs unpruning > > Hi! > > I'm a little unclear on this, so I'd like to make sure I'm not missing > any important technique - is "progressive widening" and "progressive > unpruning" synonymous? > > I have looked both into the pMCTS and the CrazyStone papers and it > seems that "widening" differs from "unpruning" in that certain number of > simulations is first made before limiting the number of searches. Which > of the variants is commonly used? What "speed" of widening works for you > best? > > Thanks, > > -- > Petr "Pasky" Baudis > A lot of people have my books on their bookshelves. > That's the problem, they need to read them. -- Don Knuth > _______________________________________________ > 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/
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