RE: Fwd: Re: computer-go: How many bits are needed to encode an N x N Go position?

[Jean-Pierre Vesinet <jpvesinet@xxxxxxxxxx>]

> If you are striving for minimum bits to encode a position, 
> then reserving
> enough bits for 25 possible ko positions might be overkill: a 
> point can
> only possibly be ko in very limited circumstances. It must be 
> well under
> an eighth of the points, even in the most artificial 
> situation, so 3 bits
> (or more?) could be saved.

Yes, you are right. 25 is too much. How many possible ko mouths can coexist
on a 5x5 board for a given player? If it is less than 8, a single basic
ko-forbidden point could be encoded in 3 bits.

Let's see, O to play. Possible basic ko-forbidden points = '+'

+ X O X +
X O . O X
+ X O X +
X O . O X
+ X O X +

Hard to squeeze in more than 6 open ko mouths...

000 means no ko forbidden point,
001 means first possible ko mouth,
...
111 means seventh possible ko mouth (if such a situation exists).

Jean-Pierre