On Tue, 2007-07-10 at 16:14 +0200, chrilly wrote: > I have no finished a plain vanilla 9x9 Suzie-UCT Version. The UCT-tree is > stored in a Hashtable. I am interested who else uses this approach. > The reason for using a hashtable was: I was too lazy to implement an > explicit tree. At least at 9x9 I have no problem with memory size. In fact > there are 2 hashtables, one for the Alpha-Beta and one for the UCT-Version. > With the default parameters each version uses 160 MB. > > A chessprogrammer in Go-Land, part X: > I interpreted SuperKo as repetition of position (which seems to be correct, > although Stefan Mertin told me, there are numerous versions of SuperKo). I > used the Nimzo/Hydra code to detect this. But there is a - not a very > subtle - difference between Go and Chess. > A move which generates a repetition of position is in Chess legal, in Go it > is'nt. But I assumed its legal and had quite complicated and buggy code to > handle this case. I did not know how to evaluate it. It came not to my mind, > that its just an illegal move and one only has to generate the nextbest one. > Stefan Mertin told me the difference several times, but it did not help, > only the advice of Peter Woitke, just delete this stupid code, was the right > instruction level.
Most programs use positional superko which means that it's illegal to repeat a position although this doesn't apply to pass - it's always legal to pass even if though it repeats the previous position. Note that it doesn't matter who's turn to move it is in positional superko. If a move would repeat a board configuration (even if it's a different side to move) it's considered illegal. There are other ko rules which discriminate and depending on who you ask some are more correct than others. The difference from chess is that it's just plain illegal to repeat in GO. In chess it's legal, but a draw if the opponent claims it. Most chess programs code it up as an instant draw. - Don > Chrilly > > _______________________________________________ > computer-go mailing list > [email protected] > http://www.computer-go.org/mailman/listinfo/computer-go/ _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
