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[Bug-gsl] [bug #45730] Inaccurancy problems in the function bessel_j2
From: |
Enyi Tang |
Subject: |
[Bug-gsl] [bug #45730] Inaccurancy problems in the function bessel_j2 |
Date: |
Tue, 11 Aug 2015 01:01:02 +0000 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.89 Safari/537.36 |
URL:
<http://savannah.gnu.org/bugs/?45730>
Summary: Inaccurancy problems in the function bessel_j2
Project: GNU Scientific Library
Submitted by: eytang
Submitted on: Tue 11 Aug 2015 01:01:01 AM GMT
Category: Accuracy problem
Severity: 3 - Normal
Operating System:
Status: None
Assigned to: None
Open/Closed: Open
Release: GSL-1.16
Discussion Lock: Any
_______________________________________________________
Details:
I find the result of gsl_sf_bessel_j2 at large input is wrong. But the results
of gsl_sf_bessel_j0 and gsl_sf_bessel_j1 are right. A test case is attached,
and I will further investigate the reason and may provide some clues from the
code. The outputs of the attached test case are as follows with the latest
version of GSL in git. The version hash is
867624b55b20de8da80d23d90549c74ec24cb3a6 on Aug. 7, 2015.
gsl_sf_bessel_j0(-1.000000e+22): -0.000000
gsl_sf_bessel_j1(-1.000000e+22): 0.000000
gsl_sf_bessel_j2(-1.000000e+22):
183552123001419854904449771500981977088.000000
gsl_sf_bessel_j0(-1.000000e+21): -0.000000
gsl_sf_bessel_j1(-1.000000e+21): 0.000000
gsl_sf_bessel_j2(-1.000000e+21): -92157107960277832260219441795563520.000000
gsl_sf_bessel_j0(-1.000000e+20): -0.000000
gsl_sf_bessel_j1(-1.000000e+20): 0.000000
gsl_sf_bessel_j2(-1.000000e+20): -9155440021830429048832.000000
gsl_sf_bessel_j0(-1.000000e+19): -0.000000
gsl_sf_bessel_j1(-1.000000e+19): -0.000000
gsl_sf_bessel_j2(-1.000000e+19): 2.888382
gsl_sf_bessel_j0(-1.000000e+18): -0.000000
gsl_sf_bessel_j1(-1.000000e+18): 0.000000
gsl_sf_bessel_j2(-1.000000e+18): 0.000000
gsl_sf_bessel_j0(-1.000000e+17): -0.000000
gsl_sf_bessel_j1(-1.000000e+17): -0.000000
gsl_sf_bessel_j2(-1.000000e+17): 0.000000
gsl_sf_bessel_j0(1.000000e+17): -0.000000
gsl_sf_bessel_j1(1.000000e+17): 0.000000
gsl_sf_bessel_j2(1.000000e+17): 0.000000
gsl_sf_bessel_j0(1.000000e+18): -0.000000
gsl_sf_bessel_j1(1.000000e+18): -0.000000
gsl_sf_bessel_j2(1.000000e+18): 0.000000
gsl_sf_bessel_j0(1.000000e+19): -0.000000
gsl_sf_bessel_j1(1.000000e+19): 0.000000
gsl_sf_bessel_j2(1.000000e+19): 2.888382
gsl_sf_bessel_j0(1.000000e+20): -0.000000
gsl_sf_bessel_j1(1.000000e+20): -0.000000
gsl_sf_bessel_j2(1.000000e+20): -9155440021830429048832.000000
gsl_sf_bessel_j0(1.000000e+21): -0.000000
gsl_sf_bessel_j1(1.000000e+21): -0.000000
gsl_sf_bessel_j2(1.000000e+21): -92157107960277832260219441795563520.000000
gsl_sf_bessel_j0(1.000000e+22): -0.000000
gsl_sf_bessel_j1(1.000000e+22): -0.000000
gsl_sf_bessel_j2(1.000000e+22): 183552123001419854904449771500981977088.000000
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Tue 11 Aug 2015 01:01:01 AM GMT Name: gslbesseljtest.c Size: 672B
By: eytang
<http://savannah.gnu.org/bugs/download.php?file_id=34621>
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?45730>
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- [Bug-gsl] [bug #45730] Inaccurancy problems in the function bessel_j2,
Enyi Tang <=