[computer-go] 10k UCT bots

[Hideki Kato]

Gunnar Farnebäck: <48307B92.9020105 at lysator.liu.se>:
>Hideki Kato wrote:
> > I didn't against you, Álvaro, rather I just made a caution for
> > programmers who will use your pseudo code as is. :)
> >
> > First, I prefer SFMT (SIMD-oriented Fast Mersenne Twister) rather
> > than integer pseudo random number generators in practice where the
> > quality of play-out is important.  Modern processors execute floating
> > operations as fast as interger ones and
> > 	picked = mt_rand() * (double) num_candidates;
> > is the simplest and safe.
>
>Please note that for uniformity purists this method has exactly the
>same problem as good_quality_int_rand() % num_candidates.

Mt_rand() has very good uniform distributions in [0..1)
while
good_quality_int_rand() % num_candidates
doesn't disribute uniformly when num_candidates is not a power of 2, 
assuming good_quality_int_rand() ranges [0..2^32 or so) due to modulo 
operations.  They are not the same, aren't they?

-Hideki

>/Gunnar
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--
gg at nue.ci.i.u-tokyo.ac.jp (Kato)