bugGNU Octave - Bugs: bug #46325, [octave forge] (control) Error...

 
 

bug #46325: [octave forge] (control) Error with rlocus plot

Submitter:  None
Submitted:  Thu 29 Oct 2015 05:08:55 PM UTC
   
 
Category:  Octave Package Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Need Info Assigned to:  None
Originator Name:  Avirup Kundu Originator Email:  -email is unavailable-
Open/Closed:  * Closed Release:  * dev
Operating System:  * GNU/Linux Fixed Release:  None
Planned Release:  None
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Mon 04 Mar 2019 04:37:31 AM UTC, comment #7: 

I think that this can be closed.
There is really nothing to do.

Doug Stewart <dastew>
Mon 04 Mar 2019 03:13:47 AM UTC, comment #6: 

Doug or Avirup - Is this still a problem with current versions of Octave and the control package? I can't tell what this bug is about enough to even try to reproduce it myself.

Mike Miller <mtmiller>
Group Member
Sun 01 Nov 2015 02:51:35 PM UTC, comment #5: 

Re-posting comments which are present in e-mail, but not in Savannah's bug tracker.

Sorry, I don't know why the description didn't save. Here it is:

I used the command


gh = tf([1],[1 6 12 8]);
rlocus(gh)


The root locus which is supposed to go off to infinity does not go off to infinity and is terminated.  This seems to be the problem with all plots going off to infinity.

Upon clicking the autoscale button, the plot vanishes, only the dotted line representing asymptotes remain.

If I use


gh1 = tf([1],[1 6]);
rlocus(gh1)


and click autofocus, the entire plot disappears only the legend remains.

Also the coloured dots used to mark the poles and zeros are not visible.  Can anything be done to solve that?


I get it that higher roots are difficult to handle.  But if the graph itself disappears on clicking the Autoscale button, that is a rendering bug right?  Attaching screenshots, if that helps.


Rik <rik5>
Group administrator
Sun 01 Nov 2015 11:46:22 AM UTC, comment #4: 

I have no idea why I can't post the description. It's not saving the text. It's available on the email, but it's not displaying here.




I get it that higher roots are difficult to handle. But if the graph itself disappears on clicking the Autoscale button, that is a rendering bug right?
Attaching screenshots, if that helps.

Thanks for the tip Doug. Any idea on how I can change the size and characters used to plot the poles and zeros? That would be really helpful.

Avirup Kundu <avirup>
Sun 01 Nov 2015 11:40:04 AM UTC, comment #3: 

Sorry, I don't know why the description didn't save. Here it is:

I used the command +verbatim+ gh = tf([1],[1 6 12 8]); rlocus(gh) -verbatim-.

The root locus which is supposed to go off to infinity does not go off to infinity and is terminated.This seems to be the problem with all plots going off to infinity.

Upon clicking the autoscale button, the plot vanishes, only the dotted line representing asymptotes remain.

If I use +verbatim+ gh1 = tf([1],[1 6]); rlocus(gh1) -verbatim- and click autofocus, the entire plot disappears only the legend remains.

Also the coloured dots used to mark the poles and zeros are not visible. Can anything be done to solve that?




I get it that higher roots are difficult to handle. But if the graph itself disappears on clicking the Autoscale button, that is a rendering bug right? Attaching screenshots, if that helps.

Thanks for the tip Doug. Any idea on how I can change the size and characters used to plot the poles and zeros? That would be really helpful.



Avirup Kundu <avirup>
Fri 30 Oct 2015 05:03:47 PM UTC, comment #2: 

The problem is that you have a triple root at -2.
Higher order roots are always hard to handle.
You can override the default k by telling it what k you want
 [RLDATA, K] = rlocus (SYS, INCREMENT, MIN_K, MAX_K)
I don't think that this is a bug.

Doug Stewart <dastew>
Fri 30 Oct 2015 04:53:34 PM UTC, comment #1: 

There was no description attached to this report.

Rik <rik5>
Group administrator
Thu 29 Oct 2015 05:08:55 PM UTC, original submission:  

I used the command +verbatim+ gh = tf([1],[1 6 12 8]) -verbatim- to generate the transfer function and then +verbatim+ rlocus(gh) -verbatim- to generate the root locus.

The root locus which is supposed to go off to infinity does not go off to infinity and is terminated.This seems to be the problem with all plots going off to infinity.

Upon clicking the autoscale button, the plot vanishes, only the dotted line representing asymptotes remain.

If I use +verbatim+ gh1 = tf([1],[1 6]); rlocus(gh1) -verbatim- and click autofocus, the entire plot disappears only the legend remains.

Also the coloured dots used to mark the poles and zeros are not visible. Can anything be done to solve that?


Anonymous

 

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Attached Files
file #35355:  After Autoscale.png added by avirup (18KiB - image/png)
file #35354:  Before Autoscale.png added by avirup (26KiB - image/png)

 

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  • -email is unavailable- added by paramaniac
  • -email is unavailable- added by avirup (Updated the item)
  • -email is unavailable- added by dastew (Posted a comment)
  • -email is unavailable- added by rik5 (Posted a comment)
  • -email is unavailable- added by None (Submitted the item)
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    Follow 8 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-03-10 rik5 Open/ClosedOpen Closed
    2019-03-04 mtmiller CategoryPlotting Octave Package
        Release4.0.0 dev
        SummaryError with rlocus plot [octave forge] (control) Error with rlocus plot
    2015-11-01 paramaniac Carbon-Copy- Added paramaniac
    2015-11-01 avirup Attached File- Added After Autoscale.png, #35355
    2015-11-01 avirup Attached File- Added Before Autoscale.png, #35354
    2015-10-30 rik5 StatusNone Need Info

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