Nice to hear that :)
2009/6/5 Michael Williams <michaelwilliam...@gmail.com>: > Łukasz Lew wrote: >> >> On Wed, Jun 3, 2009 at 00:56, Michael Williams >> <michaelwilliam...@gmail.com> wrote: >>> >>> Two things: Firstly, I'm storing (only in RAM) the precalculated Winrate >>> and InvSqrtVisits and keeping them updated. >>> So my UCT formula went from >>> >>> Wins / Visits + sqrt(lnParentVisits / Visits) >>> >>> to >>> >>> WinRate + sqrtLnParentVisits * InvSqrtVisits; >>> >>> This has a memory cost, but I don't care so much about RAM since I can >>> send >>> the nodes to disk. >>> >>> And the second thing is to store in the parent node a reference to what >>> is >>> likely the UCT-best child node. If the parent has been visited >>> 100*boardspaces times, I will go directly to the likely-best child with >>> probability 2047/2048. Anytime a proper UCT loop occurs, the likely-best >>> reference is updated (about 90% of the time there is no change, so I >>> think >>> it's safe). >> >> This is quite similar to epsilon trick described here: >> http://www.mimuw.edu.pl/~lew/files/epsilon_trick.pdf >> >> in short when you calculate best UCT child you visit it >> max(best.visit_count * epsilon, 1) times >> with epsilon = 0.05 for instance >> It works well both for new and old nodes, but you have to keep the >> counter of visits. >> The soft way would be to recalculate best child with probability >> min(1, 1/(best.visit_count*epsilon)). >> >> Both variants of ET can give you some guarantees about the way the >> tree is explored. >> >> Łukasz > > > I switched to this method. Thanks, Lukasz. > > _______________________________________________ > 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/
