[computer-go] Crazystone patterns

[Rémi Coulom]

Chris Fant a écrit :
> Does this mean that you need to calculate the Bradley-Terry
> probability for every legal move before selecting one on that
> probability?  Isn't that expensive?  Have you tried selecting only N
> legal candidates at random and then selecting one of those based on
> their Bradley-Terry probability distribution to save time?
I only keep light-weight local features in the random simulations. So, 
it is not expensive. A table of move urgencies can be updated 
incrementally after each move: only a few change. In fact, my program 
became faster when I introduced 3x3 patterns for the random simulations. 
I can pre-compute a lot of information indexed by pattern shape, that 
are useful to detect eyes and move legality. From memory, Crazy Stone 
does about 5k playouts / second from the empty position on 19x19, on one 
3 GHz CPU, which is "only" about 5 times slower than libego, if I 
remember correctly.

Rémi