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[Bug-gsl] [bug #39466] errors in gsl_sf_coupling_6j_e and gsl_sf_couplin
From: |
Patrick Alken |
Subject: |
[Bug-gsl] [bug #39466] errors in gsl_sf_coupling_6j_e and gsl_sf_coupling_9j_e |
Date: |
Thu, 11 Jul 2013 17:49:48 +0000 |
User-agent: |
Mozilla/5.0 (X11; Linux i686 on x86_64; rv:22.0) Gecko/20100101 Firefox/22.0 |
URL:
<http://savannah.gnu.org/bugs/?39466>
Summary: errors in gsl_sf_coupling_6j_e and
gsl_sf_coupling_9j_e
Project: GNU Scientific Library
Submitted by: psa
Submitted on: Thu 11 Jul 2013 05:49:47 PM GMT
Category: Runtime error
Severity: 3 - Normal
Operating System:
Status: None
Assigned to: None
Open/Closed: Open
Release:
Discussion Lock: Any
_______________________________________________________
Details:
The coupling of three spins requires the total sum to be integer. This is
not checked on gsl_sf_coupling_6j_e or gsl_sf_coupling_9j_e.
We discovered it when trying to evaluate the 9j symbol:
(1/2 1/2 1/2)
(1/2 1/2 1/2)
( 0 0 0 )
and got a non-zero result. We believe that the recursive calculations of
6j should have given the zero, but found also that lacking similar checks.
The attached patch also include some test cases. The 6js have been
cross-checked with Mathematica.
Best regards,
Håkan Johansson
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Thu 11 Jul 2013 05:49:47 PM GMT Name: coupling_6_9_halfint_check.diff
Size: 3kB By: psa
<http://savannah.gnu.org/bugs/download.php?file_id=28544>
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- [Bug-gsl] [bug #39466] errors in gsl_sf_coupling_6j_e and gsl_sf_coupling_9j_e,
Patrick Alken <=