bugGNU Octave - Bugs: bug #49295, [octave forge] (control) tf object...

 
 

bug #49295: [octave forge] (control) tf object gives wrong results with impulse (and initial)

Submitter:  None
Submitted:  Sat 08 Oct 2016 12:53:42 AM UTC
   
 
Category:  Octave Package Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Fixed Assigned to:  None
Originator Name:  Juan C. Cockburn Originator Email:  -email is unavailable-
Open/Closed:  * Closed Release:  * 4.0.2
Operating System:  * GNU/Linux Fixed Release:  None
Planned Release:  None
* Mandatory Fields

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Tue 06 Mar 2018 02:30:12 AM UTC, comment #1: 

This can be closed now.
the fix is in control-3.1.0

this works.

clear
% Impulse response test
  t=linspace(0,5,51); % time vector
% create transfer function
  H=tf(1,[1 1]);
% impulse response - analytic expression
  ht=exp(-t)';
% impulse response - numerical
  ht_num=impulse(H,5,0.1);
% difference (should be close to eps) but is not !
 err=ht - ht_num;

%% Then repeat but with state-space object
  Hss=ss((tf(1,[1 1]))); % create state-space object
% numerical simulation
  ht_num_ss=impulse(Hss,5,0.1);
% difference is as expected
  err_ss=ht - ht_num_ss


Doug Stewart <dastew>
Sat 08 Oct 2016 12:53:42 AM UTC, original submission:  


% Control package version 3.0.0
% Impulse response test
  t=linspace(0,T,150); % time vector
% create transfer function
  H=tf(1,[1 1]);
% impulse response - analytic expression
  ht=exp(-t)';
% impulse response - numerical
  ht_num=impulse(H,t);
% difference (should be close to eps) but is not !
 err=ht - ht_num;

%% Then repeat but with state-space object
  Hss=ss((tf(1,[1 1])); % create state-space object
% numerical simulation
  ht_num_ss=impulse(Hss,t);
% difference is as expected
  err_ss=ht - ht_num_ss


Anonymous

 

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  • -email is unavailable- added by i7tiol (Updated the item)
  • -email is unavailable- added by dastew (Posted a comment)
  • -email is unavailable- added by jwe (Updated the item)
  • -email is unavailable- added by None (Submitted the item)
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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2018-03-07 i7tiol StatusNone Fixed
        Open/ClosedOpen Closed
    2017-08-13 jwe Summarytf object gives wrong results with impulse (and initial) [octave forge] (control) tf object gives wrong results with impulse (and initial)

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