On Tue, May 12, 2009 at 6:47 PM, Dave Dyer <dd...@real-me.net> wrote:
> > > > >I assume Dave Dyer does not understand alpha beta pruning either, or he > would not assume the branching factor is 361. > > The branch at the root is about (361-move number) - you have to consider > all top level moves. A/B only kicks in by lowering the average branching > factor at lower levels. > > If you're trying to save and reuse trees to reduce work, alpha beta makes > most of the saved nodes useless for anything outside the principle > variation. > This is precisely because the nodes were mostly not fully explored, and all > you know (from the previous evaluation) is that this node is better or > worse > than some other, now-irrelevant branch. But then MCTS is invalid. The point is that you do spend time learning that these nodes are not relevant, so you might as well try to remember that. If you are playing a game of chess and fall for a trap, do you consider it silly to try to remember this for the next game? - Don > > > I did a lot of work trying to reuse trees for iterative deepening > of alpha-beta searches. It required a lot of bookkeeping and a lot > of memory, and it didn't turn out to be a good strategy even for > small searches where the memory was essentially cost free. > > I suppose it's possible there's something fundamentally different here, > but you ought to think carefully before investing in terrabyte memories. > > _______________________________________________ > computer-go mailing list > computer-go@computer-go.org > http://www.computer-go.org/mailman/listinfo/computer-go/ >
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