If you remove the limit on the tree size, does this still occur? Otherwise, I agree with Gonçalo - it seems unlikely. When I implemented Double Step [1] and had weird results I forgot to switch the perspective of the bots and even worse some of the move generation was buggy.
Cheers, Tobi [1] a theoretical/simple game used in one of my favorite papers to show the laziness of monte carlo tree search when in front http://www.althofer.de/mc-laziness.pdf On 11/06/2015 07:59 PM, Gonçalo Mendes Ferreira wrote: > That doesn't seem very realistic. I'd guess your prior values are > accurate but the simulations are biased or not representative. Or you > miss precision in your transition quality floating points. Or there's > a bug related to being an adversarial problem and you didn't have the > robots swap colors? :) > > Do tell what it was when you discover the problem. > > Gonçalo F. > > On 06/11/2015 18:48, Dave Dyer wrote: >> Developing a UCT robot for a new game, I have encountered a >> surprising and alarming behavior: the longer think time the >> robot is given, the worse the results. That is, the same robot >> given 5 seconds per move defeats one give 30 seconds, or 180 seconds. >> >> I'm still investigating, but the proximate cause seems to be >> my limit on the size of the UCT tree. As a memory conservation >> measure, I have a hard limit on the size of the stored tree. After >> the limit is reached, the robot continues running simulations, refining >> the outcomes based on the existing tree and random playouts below >> the leaf nodes. >> >> My intuition would be that the search would be less effective in this >> mode, but producing worse results (as measured by self-play) is >> strongly counter intuitive. >> >> Does it apply to Go? Maybe not, but it's at least an indicator >> that arbitrary decisions that "ought to" be ok can be very bad in >> practice. >> > > _______________________________________________ > Computer-go mailing list > Computer-go@computer-go.org > http://computer-go.org/mailman/listinfo/computer-go _______________________________________________ Computer-go mailing list Computer-go@computer-go.org http://computer-go.org/mailman/listinfo/computer-go
