From: "Jari Häkkinen" <jari@chiralcomp.com>
To: Brian Gough <bjg@network-theory.co.uk>
Cc: gsl-discuss@sources.redhat.com
Subject: Re: rng question
Date: Fri, 09 Dec 2005 13:49:00 -0000 [thread overview]
Message-ID: <43998B68.8040903@chiralcomp.com> (raw)
In-Reply-To: <17303.16636.732007.363616@hp2.network-theory.co.uk>
[-- Attachment #1: Type: text/plain, Size: 1134 bytes --]
No, the attached program does not return from the call to
gsl_rng_uniform_int.
The problem shows up on my powermac running MacOSX 10.4.3 with gcc
version powerpc-apple-darwin8-gcc-4.0.0 (GCC) 4.0.0 20041026 (Apple
Computer, Inc. build 4061).
I compile GSL from CVS (20051208 = today) with with flags -NDEBUG -O2.
The test program is compiled with a plain 'gcc -o rnd_test rnd_test.c
-lgsl'.
Now, I also run the test program on a SuSE based machine, and the call
fails with an floating point exception as expected.
Jari
Brian Gough wrote:
> Jari Häkkinen writes:
> > According to the documentation gsl_rng_max(rng_ returns the maximum
> > random number the underlying rng can give, and
> > gsl_rng_uniform_int(rng,gsl_rng_max(rng)) will return
> > [0,gsl_rng_max(rng)-1]. This will not give the maximum number from the
> > underlying generator, so I tried
> > gsl_rng_uniform_int(rng,gsl_rng_max(rng)+1) but this call does not
> > return (since the second argument becomes 0).
>
> Doesn't it give an exception? (due to division by zero in the expression scale = range / n;)
> What platform are you using?
>
[-- Attachment #2: rnd_test.c --]
[-- Type: text/plain, Size: 280 bytes --]
#include <gsl/gsl_rng.h>
int main(const int argc,const char* argv[])
{
gsl_rng_env_setup();
gsl_rng* rng=gsl_rng_alloc(gsl_rng_default);
unsigned long max=gsl_rng_max(rng);
printf("%u\n",max+1);
unsigned long number=gsl_rng_uniform_int(rng,max+1);
printf("%u\n",number);
}
next prev parent reply other threads:[~2005-12-09 13:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-07 10:25 Jari Häkkinen
2005-12-07 20:07 ` Brian Gough
2005-12-09 13:49 ` Jari Häkkinen [this message]
2005-12-17 16:50 ` Brian Gough
2005-12-17 23:58 ` Jari Häkkinen
2008-08-03 23:32 RNG question Robert G. Brown
2008-08-05 9:05 ` Fabian Bastin
2008-08-08 11:12 ` Brian Gough
2008-08-08 12:33 ` Robert G. Brown
2008-08-11 20:47 ` Brian Gough
2008-08-18 21:12 ` Robert G. Brown
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