bugGNU Octave - Bugs: bug #43344, specfun: Jacobian elliptic dn()...

 
 

bug #43344: specfun: Jacobian elliptic dn() precision loss

Submitted by:  Hartmut Henkel <hhenkel>
Submitted on:  Wed 01 Oct 2014 09:26:01 PM UTC  
 
Category: Octave FunctionSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Incorrect Result
Status: FixedAssigned to: None
Originator Name: Hartmut HenkelOpen/Closed: Closed
Release: otherOperating System: GNU/Linux

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Thu 02 Oct 2014 03:38:25 AM UTC, comment #1:

Thanks for your bug report. The ellipj function has been incorporated into Octave beginning with version 3.8.0, the one provided by the specfun package has been removed (although I'm not sure if the specfun package has seen a release since then). I applied your change to the ellipj function in Octave's library and added a test case for continuity as suggested by your examples.

http://hg.savannah.gnu.org/hgweb/octave/rev/068a3e51b7b8

As a point of comparison, scipy seems to suffer from the same bug, see https://github.com/scipy/scipy/issues/3904.

Mike Miller <mtmiller>
Project Administrator
Wed 01 Oct 2014 09:26:01 PM UTC, original submission:

Bug in specfun-1.1.0.tar.gz, file ellipj.cc, function sncndn() in line 116: dn(K(m),m) gives wrong result. Error demonstration:

Bug is known already since approx. 2001, see e. g.,
http://bugs.alglib.net/view.php?id=573

sn() and cn() are not affected. Fix is straight-forward: Use dn() definition from A&S 16.1.5. Patch is attached.

Hartmut Henkel <hhenkel>

 

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Attached Files
file #32208:  ellipj.cc.patch added by hhenkel (268B - text/x-diff - Patch file,1 line to be changed.)

 

Depends on the following items: None found

Items that depend on this one: None found

 

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  • -unavailable- added by mtmiller (Posted a comment)
  • -unavailable- added by jordigh (Updated the item)
  • -unavailable- added by hhenkel (Submitted the item)
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    Follow 5 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Thu 02 Oct 2014 03:38:25 AM UTCmtmillerCategoryOctave Forge Package=>Octave Function
      StatusPatch Submitted=>Fixed
      Open/ClosedOpen=>Closed
    Wed 01 Oct 2014 09:43:18 PM UTCjordighStatusNone=>Patch Submitted
    Wed 01 Oct 2014 09:26:01 PM UTChhenkelAttached File-=>Added ellipj.cc.patch, #32208

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