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. > This is true in GO too. I'm talking about the kinds of position where go program start to play "aimlessly" and they only do that when the result is like being down a queen in chess. Even being down a piece in chess is playable if there is some compensation.
> 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. > I still say that go programs are not that smart, so when one of these positions arise it isn't a position that is difficult for pro's to win. If an MC programs thinks it has 5% chance to win, it's probably still playing for that 5% chance and will still play reasonable (although perhaps what we might consider "foolishly risky" moves.) At the point that it is pretty sure it is losing, perhaps 5% or less, it's like being a queen down in chess - it's going to lose and the nice nuances you are talking about don't exist. The positions you are talking about are still playable. I still keep seeing this misconception that MC programs are really sloppy and do not care about that last few points - that could not be farther from the truth. If the game is hanging on a critical move where 1 or 2 stones makes a difference, the programs is going to entirely focused on that. We forget the program is trying to be absolutely SAFE and will do anything it can to increase the winning probability. It is NOT playing foolishly risky and "squandering away" a win because it doesn't care about a few unimportant stones. THAT is precisely what a human player might do because he loses track of the exact score, or the game is close and he misses an extra critical stone here and there. > 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. > My point is that if you need to catch up, you probably go outplayed ANYWAY early on and the odds are good that you are losing if you think your are losing with 95+ percent probability. 95% probability isn't about how many stones ahead or behind, it is an estimate of probability of winning and it could be 1/2 point or 50 points if those points are contested. If there is a fight between just 3 or 4 points that could go either way, the program is keenly aware of this and doesn't waste moves (we are judging things relatively, of course a much stronger player might think it's wasting moves but from the point of view of the program it is "fully engaged" and playing up to it's ability.) > 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/
