[Octave-bug-tracker] [bug #55201] Wrong result while dividing matrices

[anonymous]

URL:
  <https://savannah.gnu.org/bugs/?55201>

                 Summary: Wrong result while dividing matrices
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Tue 11 Dec 2018 09:15:29 AM UTC
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Shotem
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.4.1
        Operating System: Microsoft Windows

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Details:

The error occurs in some occasions when trying to divide or multiply times the
inverse of a matrix

For example:

A = [3, -2; 1, 2]
v = [-4, 12]
v/A


Output:

ans =

-2.50000 3.50000


The same happened when I tried to multiply

v*inv(A)


The expected output is:

ans =

2 5


The same problem wasn't found in the following case:

A = [2, 1; 1, 3]
v = [5, 10]
v/A


Output:

ans =

1.00000 3.00000


When the answer matched the expected result.

The answers in both cases were revised using an external tool (Geogebra
Version: 6.0.513.0-offline)

Note:
The notation used does not affect the results as shown in the image.



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File Attachments:


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Date: Tue 11 Dec 2018 09:15:29 AM UTC  Name: Captura.PNG  Size: 38KiB   By:
None

<http://savannah.gnu.org/bugs/download.php?file_id=45624>

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