GNU Scientific Library - Bugs: bug #42042, nan bug in bessel_Jnu
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bug #42042: nan bug in bessel_Jnu
Submitter: | Patrick Alken <psa> | ||
Submitted: | Thu 03 Apr 2014 09:36:21 PM UTC | ||
Category: | Runtime error | Severity: | 3 - Normal |
Operating System: | Status: | None | |
Assigned to: | None | Open/Closed: | Open |
Release: |
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Depends on the following items: None found
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Hello everyone,
I have this particular problem where I need
gsl_sf_bessel_Jnu(0.5, 3/2 * pi)
and I tested it with the following code:
#include <stdio.h>
#include <math.h>
#include <gsl/gsl_sf_bessel.h>
int
main (void)
{
double y1 = gsl_sf_bessel_Jnu(0.5, 3.0/2.0 * M_PI+1e-15);
double y2 = gsl_sf_bessel_Jnu(0.5, 3.0/2.0 * M_PI);
printf ("%e vs. %e\n", y1, y2);
return 0;
}
Output:
-3.675526e-01 vs. nan
MATLAB e.g. does return the correct value for 3/2 * pi. Is this a bug in
the implementation of the function? It seems so and I have not found
documentation about irregularities at 3/2 PI.