bugGNU Octave - Bugs: bug #33932, Permutation matrices of class...


bug #33932: Permutation matrices of class 'single' are unsupported

Submitted by:  Rik <rik5>
Submitted on:  Wed 03 Aug 2011 02:18:04 AM UTC  
Category:  Libraries Severity:  2 - Minor
Priority:  1 - Later Item Group:  Matlab Compatibility
Status:  None Assigned to:  None
Originator Name:  Open/Closed:  Closed
Release:  dev Operating System:  Any

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Mon 28 Aug 2017 08:17:27 PM UTC, comment #4:

Can anyone with access to Matlab verify the class of P? If not, we can post on Octave-Maintainer's list. Sample code:

Also, even if they do return a single matrix, do we care enough to fix this? Memory isn't a concern. The LU decomposition results in

If A is single, L and U will be single, and a double matrix P multiplied by a single matrix A will result in an object of class single.

Rik <rik5>
Project Administrator
Mon 28 Aug 2017 06:03:31 PM UTC, comment #3:

I think this is still a compatibility issue as I suspect Matlab creates a single precision array for P in

John W. Eaton <jwe>
Project Administrator
Sat 26 Aug 2017 05:22:42 AM UTC, comment #2:

I don't think we need to change anything. Permutation matrices are already very space efficient so there is no real memory issue with storing the indices as double values rather single values. I can't find the original code in ov-re-mat.cc so it has probably been removed. Closing report.

Rik <rik5>
Project Administrator
Sat 19 Nov 2016 03:18:37 PM UTC, comment #1:

This behavior is still present in Octave 4.2.0.

Hartmut <hardy>
Wed 03 Aug 2011 02:18:04 AM UTC, original submission:

This is a placeholder issue report. During the first code sprint it was found that permutation matrices can only be created of class double. This might not be a problem, however, we found C++ code for the double() function (src/ov-re-mat.cc) that was checking for permutation matrices of type single.

Example Code:

Rik <rik5>
Project Administrator


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    Follow 8 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    Mon 28 Aug 2017 06:03:31 PM UTC jwe Item GroupOther => Matlab Compatibility
        StatusWont Fix => None
    Sat 26 Aug 2017 05:22:42 AM UTC rik5 StatusConfirmed => Wont Fix
        Open/ClosedOpen => Closed
    Sun 19 Jan 2014 10:57:40 PM UTC mtmiller CategoryNone => Libraries
        Operating SystemGNU/Linux => Any
    Fri 08 Jun 2012 09:37:34 PM UTC rik5 Priority2 => 1 - Later
    Sun 25 Sep 2011 07:55:16 PM UTC rik5 Priority5 - Normal => 2

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