[Octave-bug-tracker] [bug #32121] logm returns complex numbers

[Guillaume]

URL:
  <http://savannah.gnu.org/bugs/?32121>

                 Summary: logm returns complex numbers
                 Project: GNU Octave
            Submitted by: gyom
            Submitted on: Thu Jan 13 19:57:42 2011
                Category: Libraries
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Guillaume
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: GNU/Linux

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Details:

logm sometimes returns complex numbers with Octave dev, while it doesn't with
Octave 3.2.4 or MATLAB.

For example, with the attached file:
>> load R.mat
>> lR = logm(R)

Octave dev returns:
lR =
  -2.6321e-16 - 1.3010e-18i  -1.5583e-03 + 3.4694e-18i  -3.6555e-02 -
5.2042e-18i
   1.5583e-03 + 6.9389e-18i   1.2423e-16 - 4.1633e-17i   1.9404e-01 +
2.0817e-17i
   3.6555e-02 - 5.2042e-18i  -1.9404e-01 + 2.0817e-17i  -6.9390e-16 +
1.3878e-17i


while Octave 3.2.4 returns:
lR =
  -1.4738e-16  -1.5583e-03  -3.6555e-02
   1.5583e-03   4.1562e-16   1.9404e-01
   3.6555e-02  -1.9404e-01  -6.0125e-16

and MATLAB returns:
lR =
   -0.0000   -0.0016   -0.0366
    0.0016    0.0000    0.1940
    0.0366   -0.1940   -0.0000




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File Attachments:


-------------------------------------------------------
Date: Thu Jan 13 19:57:42 2011  Name: R.mat  Size: 384B   By: gyom

<http://savannah.gnu.org/bugs/download.php?file_id=22403>

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