Re: [gnugo-devel] rand() % n

[David G Doshay]

On May 13, 2004, at 2:26 PM, Paul Pogonyshev wrote:

> Custom generator is used because we want GNU Go to behave identically
> on (ideally) all operating systems and not depend on such things as
> system-specific RNGs.

Perfectly reasonable.

> Therefore a built-in generator is needed.  It
> is there and it is good (much better than would fit GNU Go's needs).

I was really wondering why so much time was being spent worrying
about the low order bits when it does seem that most any decent RNG
(and perhaps even a known poor one) would be far better than this
application would require. I am reading the relevant code now, but
given what I have seen so far from genmove results, I feel sure that
the number of candidate moves we are choosing between will be very
small. Thus, the fine scale resolution of the RNG is irrelevant.

> But there is absolutely no reason to alter or replace it.

It was not my intent to suggest the use of another RNG, unless the
overflow problem really is an issue.

Cheers,
David