GNU Scientific Library - Bugs: bug #58069, Correction to gsl_sf_gamma_inc_Q...
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bug #58069: Correction to gsl_sf_gamma_inc_Q documentation
Submitter: | Jackson Vanover <jacksonvanover> | ||
Submitted: | Sat 28 Mar 2020 05:31:15 PM UTC | ||
Category: | Documentation | Severity: | 3 - Normal |
Operating System: | Ubuntu 18.04 | Status: | None |
Assigned to: | None | Open/Closed: | Open |
Release: | 2.6 |
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Corresponding source code
Using version 2.6 of GSL from ftp://ftp.gnu.org/gnu/gsl/gsl-2.6.tar.gz
OS is Ubuntu 18.04.2 LTS
Hardware is a Dell workstation with a 3.60 GHz Intel i7-4790 and 32 GB
of RAM
Compiler is gcc 7.4.0 with the -w option
Though the documentation for gsl_sf_gamma_inc_Q states that the first
element must be strictly greater than zero, the function returns a
zero when the first argument is equal to 0. The error handler is
invoked when the first argument is negative though. The libraries
SciPy and JMAT exhibit the same behavior so it seems as though this is
expected; perhaps the documentation should be updated then.
#include <gsl/gsl_sf.h>
#include <stdio.h>
#include <gsl/gsl_math.h>
#include <float.h>
int main (void){
double out;
out = gsl_sf_gamma_inc_Q(0, 2.2);
printf("%.*f\n", DBL_DIG-1, out);
printf("%.21e\n", out);
return 0;
}