Re: computer-go: unmake move?

[Don Dailey <drd@xxxxxxxxxxxxxxxxxxxxx>]

> I use this idea in my chess program and it is very effective.
> But the chess program board state is only 220 bytes.  Copying is
> very fast, and there is no need to unmake moves.  Many Faces
> has much more state per position, so copying to make moves
> is not practical.  And I hadn't thought of this when I first
> wrote Many Faces :)  If you can keep the move state small,
> avoiding undo by copying positions is a very good idea.
> 
> David



I guess the question is, how much state is too much?  Of course it's a
function of many factors, including  the  specific hardware used,  and
how each program is designed.  My program is pretty simple and I don't
carry a lot of state.  If  I get serious I will  have to add an unmake
routine and run some performance tests to see if  I am losing too much
(or any) performance using this technique for go.


Don