This should help: http://computer-go.org/pipermail/computer-go/2007-February/thread.html#8653
Erik On Dec 19, 2007 5:58 PM, Rémi Coulom <[EMAIL PROTECTED]> wrote: > 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 > [email protected] > http://www.computer-go.org/mailman/listinfo/computer-go/ >
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