bugGNU Scientific Library - Bugs: bug #45730, Inaccurancy problems in the...

 
 

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bug #45730: Inaccurancy problems in the function bessel_j2

Submitted by:  Enyi Tang <eytang>
Submitted on:  Tue 11 Aug 2015 01:01:01 AM UTC  
 
Category: Accuracy problemSeverity: 3 - Normal
Operating System: Status: Fixed
Assigned to: NoneOpen/Closed: Closed
Release: GSL-1.16

Sun 07 May 2017 03:44:03 PM UTC, comment #2:

fixed in commit bd5b94b47bad7f8c0beb3036cb256a341e67ad5d - switch from gsl_sf_{cos,sin} to cos/sin

Patrick Alken <psa>
Project Administrator
Thu 13 Aug 2015 06:08:15 AM UTC, comment #1:

The fixing suggestion is submitted with Bug #45746. I believe it is also helpful in fixing bug #36152.

Enyi Tang <eytang>
Tue 11 Aug 2015 01:01:01 AM UTC, original submission:

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

Enyi Tang <eytang>

 

Attached Files
file #34621:  gslbesseljtest.c added by eytang (672B - application/octet-stream)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by psa (Posted a comment)
  • -unavailable- added by eytang (Submitted the item)
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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sun 07 May 2017 03:44:03 PM UTCpsaStatusNone=>Fixed
      Open/ClosedOpen=>Closed
    Tue 11 Aug 2015 01:01:01 AM UTCeytangAttached File-=>Added gslbesseljtest.c, #34621

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