Actually, I think the solution to all of this is relatively simple. When the programs go into the state where the moves are no longer "cosmetically appealing" it's because all the moves lead to the same result, whether it be wins or losses.
That being so, one solution is to impose a different move generator, one that plays cosmetically appealing moves. As long as we can get UCT to "believe" that the pretty moves are ever so slightly better, it will play those when all else is equal. In fact, my simple program ogo and anchorman behave that way a little, since I have "imposed" some logic on the moves outside of the simulations. I have a few incentives and disincentives to encourage and discourage certain moves. If I took this a little farther you might not even realize it was a monte carlo program. - Don David Fotland wrote: >> I don't like using the words "good" and "bad" when describing the >> quality of the moves because I try to use terminology that's more >> descriptive (although I fail miserably many times.) In a lost >> position how do you distinguish one move from another when they all >> lose? It sounds funny to me when you say (in so many words) that >> once the program is losing it starts playing "bad moves." >> >> Since this is a subjective quality can we use a subjective term such as >> "normal" to describe moves that are cosmetically appealing to us? >> And perhaps "ugly" to describe moves that are not? >> >> My feeling is that in lost positions, the only thing we are trying to >> accomplish is to make the moves more cosmetically appealing (normal) >> and >> at best improve the programs chances of winning against weak players. >> After all, if the program is in bad shape, then to be completely >> realistic it's probably going to lose to the player that put it in this >> bad shape. >> > > This is chess thinking and it is not true for go. In chess if you have a > clearly lost position (like down a piece without compensation), you can only > hope for a miracle. > > But go is a game of accumulating points. Every player, even professionals, > make mistakes in the endgame and play moves that don't optimize the score. > I'm talking about endgame positions, which by definition have no unsettled > groups, so we aren't talking about moves that have different probabilities > of causing an opponent mistake. I'm talking about making a move that gains > 2 points when there is another one that gains 3 points. > > If you are objectively 3 points behind with perfect play with 100 endgame > moves to go, it is quite likely that you can catch up against a high Dan > player. Against a low Dan player you can likely catch up 5 to 10 points in > the endgame. Of course you can only catch up if you play the moves that > gain the most points every time you move. If you make a move that costs a > point while making an obvious threat, you are falling further behind. > > Good moves are the moves that gain the most points in the local situation. > Often there are several goo d local moves, for example the one that gains > the most points but lets the opponent move first elsewhere, and the one that > gains fewer points but lets me move first elsewhere. If I can gain 5 points > locally, but play a move that only gains 4 points and otherwise has no > difference, it's clear that the 4 point move is a bad move. The 5 point > move might not be the best move on the whole board (if there is a 6 point > move somewhere else), but we can still say that the 5 point move is good and > the 4 point move is bad. > > This has nothing to do with "cosmetically appealing". Once the endgame > starts and groups are solid and endgame regions become independent, then it > is all about making the move that gains the most points. > > This kind of endgame play is not obvious on 9x9 sine that board is so small > there isn't much endgame. > > David > > > > _______________________________________________ > 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/
