Hi, I have not had time to study it in details, but I found this: http://fragrieu.free.fr/zobrist.pdf
A Group-Theoretic Zobrist Hash Function Antti Huima September 19, 2000 Abstract Zobrist hash functions are hash functions that hash go positions to fixed-length bit strings. They work so that every intersection i on a go board is associated with two values Bi and Wi. To hash a position, all those values of Bi are XORed together that correspond to an intersec- tion with black stone on it. Similarly, all Wi’s are XORed together for those intersections that have a white stone. Then the results are XORed together. We present a Zobrist hash function with the extra property that if z is the hash value of a position p, then the values z′ for the positions p′ that are obtained from p by exchanging the colors, by rotating the position and my mirroring can be efficiently calculated from z alone. Still, z and z′ are different. Rémi _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
