One must decide if the goal is to improve the program or to improve it's playing behavior when it's in a dead won or dead lost positions.
It's my belief that you can probably cannot improve the playing strength soley with komi manipulation, but at a slight decrease in playing strength you can probably improve the behavior, as measured by a willingness to fight for space that is technically not relevant to the goal of winning the game. And only then if this is done carefully. However I believe there are better ways, such a pre-ordering the moves. Even if this can prove to be a gain, you are really working very hard to find something that only kicks in when the game is already decided - how to play when the game is already won or already lost. But only the case when the game is lost is this very interesting from the standpoint of making the program stronger. And even this case is not THAT interesting, because if you are losing, on average you are losing to stronger players. So you are working hard on an algorithm to beat stronger players when you are in a dead lost game? How much sense does that make? So the only realistic pay-off here is how to salvage lost games against players that are relatively close in strength since you can expect not to be in this situation very often agaist really weak players. So you are hoping to bamboozle players who are not not weaker than you - in situations where you have been bamboozled (since you are losing, you are the one being outplayed.) That is why I believe that at best you are looking at only a very minor improvement. If I were working on this problem I would be focused only on the playing style, not the playing strength. If you want more than the most minor playing strength improvement out of this algorithm, you have to start using it BEFORE the loss is clear, but then you are no longer playing for the win when you lower your goals, you are playing for the loss. - Don 2009/8/19 Stefan Kaitschick <stefan.kaitsch...@hamburg.de> > One last rumination on dynamic komi: > > The main objection against introducing dynamic komi is that it ignores the > true goal > of winning by half a point. The power of the win/loss step function as > scoring function underscores > the validity of this critique. And yet, the current behaviour of mc bots, > when either leading or trailing by a large margin, resembles random play. > The simple reason for this is that either every move is a win or every move > is a loss. > So from the perspective of securing a win, every move is as good as any > other move. > Humans know how to handle these situations. They try to catch up from > behind, or try to play safely while defending enough of a winning margin. > For a bot, there are some numerical clues when it is missbehaving. > When the calculated win rate is either very high or low and many move > candidates have almost identical win rates, the bot is in coin toss country. > A simple rule would be this: define a minimum value that has to separate > the win rate of the 2 best move candidates. > Do a "normal" search without komi. > If the minimum difference is not reached, do a new a new search with some > komi, but only allow the moves within the minimum value range from the best > candidate. > Repeat this with progressively higher komi until the two best candidates > are sufficiently separated.(Or until the win rate is in a defined middle > region) > There can be some traps here, a group of moves can all accomplish the same > critical goal. > But I'm sure this can be handled. The main idea is to look for a less > ambitious gloal when the true goal cannot be reached. > (Or a more ambitious goal when it is allready satisfied). By only allowing > moves that are in a statistical tie in the 0 komi search, > it can be assured that short term gain doesn't compromise the long term > goal. > > Stefan > > _______________________________________________ > computer-go mailing list > computer-go@computer-go.org > http://www.computer-go.org/mailman/listinfo/computer-go/ >
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