Le samedi 25 novembre 2006 00:38, alain Baeckeroot a écrit : > Le mercredi 22 novembre 2006 20:44, Rémi Coulom a écrit : > > Hi, > Hi Rémi > > > > I am in search of Go positions that are easy to understand for humans, > > and difficult for computers. > > > One incredibly simple example for human, where GNU Go horribly fails. > The only move is tengen (center of the board). > > I don't know if its a simple bug, or a more difficult evaluation problem. > It happens even if all databases are disabled (fuseki and joseki)
I investigated a little this "thickness evaluation" problem: The first player getting tengen spoils 2 opponent moves. The stones can still help for some ladders, but they can be seen as dead. So it nearly equivalent to 2 handicap game, (miai counting gives: one stone is used to kill 2, remains 2 'not used' stones), with weirdly placed handicap, so at least the advantage is greater than 1 "normal corner handicap move". I tried a simple fix in gnugo, now it find the proper move in this test case. But as a side effect: On a 19x19 it plays too slow, and lose 10/10 games agaisnt standard GNU Go. (5 as W, 5 as B, this is small sample i agree) On 9x9, it seems to have a smaller impact: as Black 5/10 games win as White 2/10 games win So at least parameter tuning is needed, maybe more refined stuff for evaluating the value of cut/connect move ... this is not simple :) QED. Alain _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
