> The basic idea is this: 90 degree rotation (to the right) is represented as > a circular shift (to the right) by 1/4 of the key length. mirroring the > board (swap left and right) is done as reversing the order of the bits in > the key. > > Distinct hash values around the board would have to share the same rules. > > Picking a somewhat arbitrary example (on 19x19), here's some candidate keys > (kept simple for manual typing) > > A2 = 0x 01 02 03 04 > B19 = 0x 04 01 02 03 > T18 = 0x 03 04 01 02 > U1 = 0x 02 03 04 01 > > T2 = 0x 20 c0 40 80 > B1 = 0x 80 20 c0 40 > A18 = 0x 40 80 20 c0 > U19 = 0x c0 40 80 20 > > Points on lines of symmetry (such as C3 with 4 equivalent points or the > unique tengen) need more care with how they're selected).
That's the same system I used in my first Go program, and it appears to also be the same as what is in the paper that Remi linked. I didn't use it for full-board hashes, I used it for patterns. _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
