bugGNU Octave - Bugs: bug #52254, [octave forge] (signal) filtic...

 
 

bug #52254: [octave forge] (signal) filtic output not compatible with MATLAB

Submitter:  None
Submitted:  Thu 19 Oct 2017 07:01:38 PM UTC
   
 
Category:  Octave Package Severity:  3 - Normal
Priority:  1 - Later Item Group:  Matlab Compatibility
Status:  Fixed Assigned to:  None
Originator Name:  Tony Richardson Originator Email:  -email is unavailable-
Open/Closed:  * Closed Release:  * other
Operating System:  * Any Fixed Release:  None
Planned Release:  None
* Mandatory Fields

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Fri 08 Feb 2019 07:54:15 PM UTC, comment #3: 

I applied a modified version of your patch, along with a test case, under your name and email

http://hg.code.sf.net/p/octave/signal/rev/78e80ff895c9

Thanks for the patch and your patience! This fix will be part of the upcoming signal version 1.4.1.

Mike Miller <mtmiller>
Group Member
Thu 06 Dec 2018 08:33:46 PM UTC, comment #2: 

A patch is attached.

(file #45590)

Tony Richardson <amrichardson>
Wed 21 Mar 2018 01:19:39 AM UTC, comment #1: 

A solution that works equally well is to divide the output by a(1) before returning from filtic.

I don't know at the moment what the right solution here is. But I can confirm that a(1) is never used inside the function as it is written currently.

Mike Miller <mtmiller>
Group Member
Thu 19 Oct 2017 07:01:38 PM UTC, original submission:  

I was getting incorrect results using the filter function.  I tracked the issue down to a problem with filtic.

b = [4 -3]; a = [2 -3 1];
filtic(b, a, [0 1])

returns [-1 0] as a result.  The correct result (and that returned by MATLAB) is [-0.5 0].

Octave returns the MATLAB result if I divide both b and a by a(1):

b = [4 -3]; a = [2 -3 1];
filtic(b/a(1), a/a(1), [0 1])

gives [-0.5 0].

An easy fix is to divide both vectors by a(1) inside the filtic function, but I am not sure that is the best solution.


Anonymous

 

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Attached Files
file #45590:  filtic.patch added by amrichardson (227B - application/octet-stream)

 

Depends on the following items: None found

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   bug dependencies.

 

Carbon-Copy List
  • -email is unavailable- added by amrichardson (Updated the item)
  • -email is unavailable- added by None (Submitted the item)
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    Follow 11 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-02-08 mtmiller StatusPostponed Fixed
        Open/ClosedOpen Closed
    2018-12-06 amrichardson Attached File- Added filtic.patch, #45590
    2018-12-06 mtmiller Carbon-CopyRemoved 80942 -
    2018-12-06 mtmiller Dependencies- bugs #55098 is dependent
    2018-04-03 mtmiller Priority5 - Normal 1 - Later
    2018-03-21 mtmiller StatusNeed Info Postponed
        Release4.2.1 other
        Operating SystemMicrosoft Windows Any
    2017-10-19 mtmiller StatusNone Need Info
        Summaryfiltic output not compatible with MATLAB [octave forge] (signal) filtic output not compatible with MATLAB

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