Don Dailey: <[EMAIL PROTECTED]>: >On Tue, 2008-08-12 at 09:55 +0900, Darren Cook wrote: >> > [The pro] was also a bit "unlucky" in the sense that Leela did not >> > understand it >> > was dead lost. >> > >> > I use quotes because had it understood better it was losing, it would have >> > put up more of a fight :-) >> >> My first impression of watching the game was that Leela was handicapped >> by having a handicap. By that I mean it would have seen itself so far >> ahead for the first few moves that is was playing arbitrarily. > >I was blasted for making that observation many months ago concerning the >possibility of handicap matches on CGOS. I thought it not a good idea >for Monte Carlo players because each player starting with a dead won or >dead lost game. The response was that it didn't matter, the programs >would still fight. > >So I yielded to the opinion of others since I am not a go player. I now >think they were probably right. MCTS still tries to maximize the >chances of winning. If you are up 8 or 9 stones, that is STILL the >right strategy isn't it? > >Also, if you are down 8 or 9 stones, maximizing your winning chances is >still the right strategy, right?
I think NO because of the model of the opponent. MCTS uses itself for the model but it's obvously not correct in hadicapped games. Hideki >I'm trying to come up with some kind of analogy to real life. How about >investing your money? Let's say you play a game where the goal is to >turn 500 thousand into 1 million dollars in 10 years. Double your money >in 10 years is not particularly difficult so if the only thing that >matters is winning this game then you would use very conservative >investments. This is like being up 9 stones because in theory you have >a relatively simple task to perform, just double your money. > >The temptation is to be foolish by thinking if you are a lot more >aggressive, you can get ahead of the game and get there faster. Surely, >if you have a good year or two, you can coast the rest of the way! Have >you ever been with someone who is about to run out of gas? They want to >drive FASTER thinking that if they get there faster, they will use less >fuel. Or maybe they just get anxious which causes you to drive a little >faster. > > >> This is a direct consequence of the UCT algorithm playing for the win, >> instead of trying to maximize the score. I'm fine with that (please see >> the archives for numerous passionate discussion on the subject), but >> surely you need an opening book to allow for the fact that evaluations >> are going to have a high error margin in the early game? >> >> (I'll go out on a limb and say black 3 was a mistake; I'm sure it is a >> win at 0.5pt komi, but I strongly suspect it is dubious at 5.5pt komi or >> higher.) >> >> >From another angle: if a UCT computer program is being given a handicap >> against a stronger player it should lie to itself about the komi at the >> start. It could then gradually adjust komi so it is at the correct value >> by the early middle game (e.g. move 6 in 9x9 go, move 30 in 19x19 go). >> Or it could keep adjusting komi (until it reaches the actual komi) so >> that it thinks it is only just winning. > >It could turn out that the best strategy is simply to let the opponent >play desperately and not over-react, because to have any chance when >giving 9 stones you must in some sense over-play it. > >- Don > >> >> Darren >> >> > >_______________________________________________ >computer-go mailing list >computer-go@computer-go.org >http://www.computer-go.org/mailman/listinfo/computer-go/ -- [EMAIL PROTECTED] (Kato) _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
