URL:
<http://savannah.gnu.org/bugs/?28267>
Summary: poor convergence region for gsl_sf_hyperg_1F1
Project: GNU Scientific Library
Submitted by: bjg
Submitted on: Fri 11 Dec 2009 08:35:17 PM GMT
Category: Accuracy problem
Severity: 3 - Normal
Operating System:
Status: Confirmed
Assigned to: None
Open/Closed: Open
Release: 1.13
Discussion Lock: Any
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Details:
The magnitude of the error is greater than the value itself for
a<<0, b>0, x>>0
gsl_sf_hyperg1F1(-3.78e+01, 2, 1.035e+02) => -7.00055e+18 +/- 3.77654e+19
-----------------------------------------------
From: Weibin Li <[email protected]>
To: [email protected]
Subject: [Bug-gsl] gsl_sf_hyperg_1F1
Date: Mon, 30 Nov 2009 15:26:11 +0100
Hi, guys
I experienced bugs with gsl_sf_hyperg_1F1. The version is gsl_1.12, but
the testing is also done with gsl_1.13, using a mac with version 10.5.8
and hp-workstation with gnome_2.24.1.
#include<stdlib.h>
#include<stdio.h>
#include<math.h>
#include "gsl/gsl_sf_hyperg.h"
int main(int argc, char **argv)
{
int ii;
double Ri;
double v0;
gsl_sf_result r;
for(ii = 10; ii< 140;ii++)
{
Ri = 2013;
v0 =38.86871 +ii*2.5e-10;
gsl_sf_hyperg_1F1_e(1.0-v0,2,2.0*Ri/v0,&r);
printf("%lg\t%14.13g\t%14.13g\n",v0,r.val,r.err);
}
return 0;
}
The output of above code shows an extremely large error. by increasing
Ri, the relative error decreases. Is there any idea to fix this?
Thank you very much.
Best
Weibin
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Fri 11 Dec 2009 08:35:18 PM GMT Name: hyperg1F1.c Size: 429B By:
bjg
<http://savannah.gnu.org/bugs/download.php?file_id=19240>
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