Its happening when you case gsl_sf_choose() to (int). Try this instead:
int nchoosetwo_gsl = (int) round(gsl_sf_choose(n,2))
On 08/02/2016 06:34 AM, Eldon, Bjarki wrote:
Dear GSL,
I'm using GSL version 1.16-5.1.3 on openSUSE-13.2-Oss on x86_64 arch.
the C code below returns a lot of 1s; is there a bug in gsl_sf_choose or am I
doing something wrong?
best regards
bjarki
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <gsl/gsl_errno.h>
#include <gsl/gsl_sf_elementary.h>
#include <gsl/gsl_sf_gamma.h>
#include <gsl/gsl_sf_exp.h>
int main()
{
unsigned int n ;
int nchoosetwo ;
for( n = 2 ; n <= 102 ; n++){
nchoosetwo = (int) ( ( (double)( n*(n-1)) )/2. ) ;
printf( "%d: %d\n", n, (nchoosetwo != (int)gsl_sf_choose( n,2)) ? 1 : 0
); }
return GSL_SUCCESS;
}
