rng/ranlxd.c

[Carsten Urbach <Carsten dot Urbach at physik dot fu-berlin dot de>]

Hi,

I downloaded gsl version 1.2 because I was interested in the project and 
especially in the double precision version of the ranlux random number 
generator. I have one remark about your implementation, I do not know 
whether this is important:

static inline unsigned long int
ranlxd_get (void *vstate)
{
  return ranlxd_get_double (vstate) * 4294967296.0;     /* 2^32 */
}

With 2^32 you will not get the whole range of the double precision 
version. To get it you would have to multiply with 2^48. Of course this is 
in general to big for a unsigned long int ... (but unsigned long long int 
would do)

This is not a serious bug, but the quality of the generator decreases.

Or I am wrong ;-)

best

Carsten Urbach

--
Carsten Urbach
e-mail: curbach@gmx.de
        Carsten.Urbach@physik.fu-berlin.de
Fon   : +49 (0)30 79 70 95 78
        +49 (0)30 838 53 742 (FU-Berlin)
	+49 (0)33762 77313 (DESY/Zeuthen)
URL: www.physik.fu-berlin.de/~urbach