bugGNU Octave - Bugs: bug #53649, [octave forge] (control) tf could...

 
 

bug #53649: [octave forge] (control) tf could be more tolerant to complex coefficient

Submitted by:  Charles Praplan <charprap>
Submitted on:  Sat 14 Apr 2018 07:35:22 AM UTC  
 
Category: Octave Forge PackageSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Missed Error or Warning
Status: Need InfoAssigned to: None
Originator Name: Charles PraplanOpen/Closed: Open
Release: 4.2.2Operating System: Microsoft Windows

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Sun 15 Apr 2018 10:24:13 AM UTC, comment #4:

Yes, same behavior as Matlab will be fine.

Charles Praplan <charprap>
Sat 14 Apr 2018 08:25:21 PM UTC, comment #3:

This is the complete output:

Warning: The numerator or denominator of this transfer function has complex-valued coefficients.

> In tf (line 360)


SYS =

(0.253+1e-18i)
---------------------
z^2 - 1.158 z + 0.411

Sample time: 0.0001 seconds
Discrete-time transfer function.

Alexander Wilms <alexanderw>
Sat 14 Apr 2018 08:19:57 PM UTC, comment #2:

Output of Matlab R2018a:

Warning: The numerator or denominator of this transfer function has complex-valued coefficients.

Alexander Wilms <alexanderw>
Sat 14 Apr 2018 08:55:31 AM UTC, comment #1:

How tolerant do you want it?
What does matlab do?

Doug Stewart <dastew>
Sat 14 Apr 2018 07:35:22 AM UTC, original submission:

Function tf could be more tolerant to complex coefficients in case of residual imaginary part due to arithmetic rounding.

See example below.

A warning would be better.

SYS=tf([0 0 0.253+j*1e-18] , [1, -1.158, 0.411], 1e-4)

Charles Praplan <charprap>

 

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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sat 14 Apr 2018 09:03:16 AM UTCmtmillerCategoryLibraries=>Octave Forge Package
      StatusNone=>Need Info
      Summarytf could be more tolerant to complex coefficient=>[octave forge] (control) tf could be more tolerant to complex coefficient

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