[computer-go] Rotate the dog or the tail?

[Darren Cook]

> Chrilly wrote:
> In all the pattern-matching articles I know off only 1 pattern
> orientation is stored and the area around the board-point is rotated.
> ...
> The size of the Pattern-Hashtable is no argument. Even with 3000
> patterns one gets at most 24000 mirror-patterns. 

I effectively rotate the pattern as found on the board, giving each of
the 8 versions a hash code and using the lowest. My pattern DB is
designed on the assumption I'll need approximately a million "rich"
patterns, where rich is used to mean they contain information on the
tactical status of the points and stones.

Needless to say they are not input by hand, and therefore don't include
don't care points.

Darren