bugGNU Octave - Bugs: bug #34605, isequal fails on diagonal matrix

 
 

bug #34605: isequal fails on diagonal matrix

Submitted by:  None
Submitted on:  Thu 20 Oct 2011 04:43:50 PM UTC  
 
Category: InterpreterSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Incorrect Result
Status: Works For MeAssigned to: None
Originator Name: Steve DuncanOriginator Email: -unavailable-
Open/Closed: ClosedRelease: 3.2.4
Operating System: GNU/Linux

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Fri 21 Oct 2011 06:10:54 PM UTC, comment #8:

Since you are using ubuntu, it should not be too hard to build Octave from source.

Start by doing

to get most of the build dependencies for Octave 3.4.x installed. Then download the sources for Octave 3.4.3, unpack them, cd to the octave-3.4.3 directory and type

If you want to be able to easily remove this copy of Octave later, I recommend installing everything below some new directory for this version of Octave by using something like

Then you can add /usr/local/octave-3.4.3/bin to your PATH, and later you can remove the entire installation just by removing the /usr/loca/octave-3.4.3 directory tree.

John W. Eaton <jwe>
Project Administrator
Fri 21 Oct 2011 02:55:36 PM UTC, comment #7:

I will do as you say and upgrade to 3.4.3.

This may take some time as I will have to build it for Kubuntu 11.10.

If I notice the same behaviour on 3.4.x I will repost a new bug. This one can be closed.

Thanks again for your time.

Steve Duncan <shd01>
Fri 21 Oct 2011 01:53:32 PM UTC, comment #6:

There are two approaches, I suppose, to dealing with this.

First, 3.2.4 is old and an unsupported version of Octave. The latest version is 3.4.3 and has many, many improvements. One choice for you would be to switch to a more recent version of Octave and see if the problem re-appears.

Second, if you really want to debug this then start Octave, use the command 'diary on', and proceed to work normally until you get a failure. Use 'diary off' and quit Octave. The entire history of commands necessary to reproduce the error will be in the file <diary> in the current working directory. Upload that file to this bug report and I can run it and see if it produces any problems in 3.2.4 or other versions of Octave. If it doesn't produce an error, however, then it is probably something on your system and I will just recommend solution 1 of upgrading to a newer version.

Rik <rik5>
Project Administrator
Fri 21 Oct 2011 12:47:04 PM UTC, comment #5:

It's happened again. This time I did "clear all" and the problem still persists:

Note that this time I am in the debug prompt, where I have put a keyboard statement in a script.

The history before this:

Steve Duncan <shd01>
Fri 21 Oct 2011 06:51:08 AM UTC, comment #4:

Thank you for your time; it is very much appreciated.

I can't reproduce it today either. But the sequence you wrote (omitting the "clear all" was definitely failing for me yesterday.

How would left-over variables have influenced the result? I confess that the variables "A" and "B" had both already been used during that session to hold quite different matrices. But I would have hoped their previous existence would have been completely erased.

My bones tell me this might be a symptom of Octave's internal state getting confused or corrupted. I'm getting hints of this after heavy sessions, when I sometimes get unexpected results which go away after I restart.

Steve Duncan <shd01>
Thu 20 Oct 2011 06:50:53 PM UTC, comment #3:

I can't reproduce this. I think you probably have leftover variables in your workspace.

Try the following:

I get 1 and 0 respectively for the isequal tests.

Rik <rik5>
Project Administrator
Thu 20 Oct 2011 04:55:07 PM UTC, comment #2:

Sorry I meant:

I was trying to log in to change this when you posted :-(

Anonymous
Thu 20 Oct 2011 04:53:48 PM UTC, comment #1:

What is I?

Jordi GutiƩrrez Hermoso <jordigh>
Project Administrator
Thu 20 Oct 2011 04:43:50 PM UTC, original submission:

Is this intended behaviour? How do I compare a matrix to the identity matrix?

Thanks,

Steve Duncan

Anonymous

 

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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Fri 21 Oct 2011 05:45:14 PM UTCrik5Open/ClosedOpen=>Closed
    Thu 20 Oct 2011 06:50:53 PM UTCrik5StatusNeed Info=>Works For Me
    Thu 20 Oct 2011 04:53:48 PM UTCjordighStatusNone=>Need Info

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