bugGNU Octave - Bugs: bug #46247, [octave forge] (control) lsim...

 
 

bug #46247: [octave forge] (control) lsim function - potential numerical problem ; various other edits

Submitted by:  Piet Wertelaers <piet>
Submitted on:  Mon 19 Oct 2015 09:58:52 AM UTC  
 
Category: Octave Forge PackageSeverity: 3 - Normal
Priority: 5 - NormalItem Group: None
Status: NoneAssigned to: None
Originator Name: pietOpen/Closed: Open
Release: 3.8.2Operating System: GNU/Linux

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Fri 23 Oct 2015 08:41:02 PM UTC, comment #4:

I've pushed a couple of changesets, the latest result can be seen here:

http://sourceforge.net/p/octave/control/ci/default/tree/inst/lsim.m

Note that it is not possible to use a scalar argument t as tfinal for continuous-time and as tstart for discrete-time models as you proposed. There would be a conflict if the user wants to plot both continuous- and discrete-time models together:

The changes will be part of the upcoming control-3.0.0 which should be ready in late October/early November 2015.
This bug report can be closed.

Lukas Reichlin <paramaniac>
Thu 22 Oct 2015 11:15:26 AM UTC, comment #3:

Lukas : many lines had been edited, but the scope has stayed limited to the help texinfo (some comments between () to be deleted), and to the function _linear_sumulation_ , and this is why these two portions as loose uploads. But here is the assembled m-file.

(file #35258)

Piet Wertelaers <piet>
Thu 22 Oct 2015 06:12:22 AM UTC, comment #2:

Piet, may I ask you for a patch created by the diff utility? If that is not possible, just attach your modified lsim.m file as a whole (not portions of it) so I can do the diff for you.

Lukas Reichlin <paramaniac>
Mon 19 Oct 2015 12:39:00 PM UTC, comment #1:

I am unsure what happened, but the original got lost (probably due to the sensitivity of savannahs markup).

Here is is again (it reads fine in the emails):

> The internal reconstruction of the time vector with dt = t(2) - t(1); and t = reshape (tinitial : dt : tfinal, [], 1); can be susceptible to round-off, rising unjustified complaints about size inconsistencies between U and T. The attempted fix gives prime importance to the len_t variable, instead of dt. On the fly, some other cosmetics are suggested, also in the help text.

Carnë Draug <carandraug>
Project Member
Mon 19 Oct 2015 09:58:52 AM UTC, original submission:
Piet Wertelaers <piet>

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach File(s):
   
   
Comment:
   

Attached Files
file #35258:  lsim_modified.m added by piet (11KiB - text/x-objcsrc - Entire m-file upon Lukas' request)
file #35242:  modified_function.txt added by piet (3KiB - text/plain - Corrected a typo abs(max(eig..)) in the function _linear_simulation_)
file #35226:  modified_function.txt added by piet (3KiB - text/plain - Re-worked PORTIONS of the file lsim.m)
file #35227:  modified_header.txt added by piet (4KiB - text/plain - Re-worked PORTIONS of the file lsim.m)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by jwe (Updated the item)
  • -unavailable- added by paramaniac (Posted a comment)
  • -unavailable- added by carandraug (Lukas Reichlin - maintainer of the control package)
  • -unavailable- added by piet (Submitted the item)
  • -unavailable- added by piet (octave control lsim)
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    Follow 7 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sun 13 Aug 2017 01:47:59 PM UTCjweSummary[control] lsim() function - potential numerical problem ; various other edits=>[octave forge] (control) lsim function - potential numerical problem ; various other edits
    Thu 22 Oct 2015 11:15:26 AM UTCpietAttached File-=>Added lsim_modified.m, #35258
    Tue 20 Oct 2015 04:43:05 PM UTCpietAttached File-=>Added modified_function.txt, #35242
    Mon 19 Oct 2015 12:39:00 PM UTCcarandraugCarbon-Copy-=>Added -unavailable-
    Mon 19 Oct 2015 09:58:52 AM UTCpietAttached File-=>Added modified_function.txt, #35226
      Attached File-=>Added modified_header.txt, #35227
      Carbon-Copy-=>Added piet

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