On 28, Oct 2008, at 12:28 PM, terry mcintyre wrote:
Sluggo has ( or had ) a particularly nasty form of "the enemy's key point is my own" - the program actually ran the GnuGo engine, so Sluggo knew precisely where GnuGo was most likely to play, and ( using a large cluster ) could give GnuGo a five stone handicap and win "convincingly and consistently", according to David Doshay, the author of Sluggo - google "sluggo gnugo evil twin" for more information.
While these things may be related, they are actually different code segments inside of SlugGo ... but the original post did mix the two somewhat as well.
The Evil Twin Effect comes from correct modeling of the opponent's play in look ahead sequences. The effect in SlugGo is strong enough in games against GNU Go that with proper parameter settings and enough look ahead SlugGo could beat GNU Go with 9 stones. But as Terry says, that apparent strength not only did not make SlugGo stronger against other programs, it made it weaker. Too much weight was placed upon long look ahead sequences which were virtually certain to happen in a game against GNU Go, and had virtually no probability of happening in a game against anyone else.
One nasty form of "The Enemy's Key Point Is My Own" was the "reverse monkey jump," where SlugGo would properly recognize that the opponent's best move against it was a monkey jump, and properly see that stopping that monkey jump was the best move, but it would then play the same exact point the opponent would have, thus playing way too far inside its own area. So, as I said in my earlier post, "near" is the right idea, not at the same point. There are other easy examples involving them extending towards our stones, where we should not take their extension as our move, but we should prevent their extension my moving into that area farther from our own stones than they would have approached.
Cheers, David _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
