URL:
<https://savannah.gnu.org/bugs/?58060>
Summary: Dropped NaN from gsl_sf_laguerre_n
Project: GNU Scientific Library
Submitted by: jacksonvanover
Submitted on: Sat 28 Mar 2020 04:33:09 PM UTC
Category: Accuracy problem
Severity: 3 - Normal
Operating System: Ubuntu 18.04
Status: None
Assigned to: None
Open/Closed: Open
Release: 2.6
Discussion Lock: Any
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Details:
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
When the degree of the laguerre polynomial is zero and the second argument
is a NaN, eval_genlaguerre returns 1.0. Despite the fact that the laguerre
polynomial of degree zero evaluates to 1 over its whole domain, the NaN
does not adhere to the domain restriction stated in the docs that the
second argument should be greater than -1.
#include <gsl/gsl_sf.h>
#include <stdio.h>
#include <gsl/gsl_math.h>
int main (void){
double out;
out = gsl_sf_laguerre_n(0, GSL_NAN, 2.2738632088209076);
printf("%f\n", out);
printf("%.21e\n", out);
return 0;
}
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