Hi Erik, > (1) They compared Rave to plain UCT. If they would have compared it to > a more sophisticated implementation (like the best Mogo before Rave) > they probably could not have shown a spectacular improvement.
The best Mogo before Rave was very close to plain UCT with the sequence-like simulations. And indeed we exactly compared the best Mogo before and after Rave. There is a table (I don't remember which number), which show the incremental improvements from plain UCT, to Rave, passing by plain UCT with sequence-like simulations. All experiments have been done with MoGo's code, all other parts of the code staying constant. There were not "secret part" of MoGo disabled to make the improvement of Rave more interesting. One discrepancy between our results and the one some of you observe, as Gian-Carlo stated, is likely to come from the parameters and detail of implementation. We heavily tuned those parameters and details against gnugo, and that makes quite a big difference. I chatted more closely with some of you about details and it did make a difference. Maybe some of you can share what made a change, if you want. Note as well that the current implementation of MoGo (not the one at the time of the ICML paper) use a different tradeoff between UCT and Rave value, thanks to an idea of David Silver, which brought improvements in 19x19 (where the Rave values are the most useful), while it was marginal (still better) in 9x9. But anyway we here are talking about 9x9, so it can't explain what you are talking about. > (2) (....) Depending on the playout > policy, adding an upper confidence bound to the rave values can push > some terrible bad moves up (like playing on 1-1). The reason seems to > be that such moves are normally sampled very infrequently (so the UCB > will be higher), and when they are selected (...) That could be an explanation, but there are two points: - the prior you put on top of Rave often avoid to first sample 1-1, and even when you do, you very often loose just 1 playout because of the UCT value you get right away. - I never observed a big discrepancy between the number of Rave samples for each move. Best, Sylvain _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
