bugGNU Octave - Bugs: bug #60427, [octave forge] (signal) decimate...

 
 

bug #60427: [octave forge] (signal) decimate function outputs divergent numbers

Submitter:  Paul Netsaver <netsaver>
Submitted:  Tue 20 Apr 2021 09:26:02 PM UTC
   
 
Category:  Octave Package Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Inaccurate Result
Status:  Confirmed Assigned to:  None
Originator Name:  Netsaver Paul Open/Closed:  * Open
Release:  * dev Operating System:  * Any
Fixed Release:  None Planned Release:  None
* Mandatory Fields

Add a New Comment Rich Markup
   

Wed 21 Apr 2021 06:02:17 PM UTC, comment #1: 

Confirmed.

To me, this looks like a small missing feature of the Octave decimate function. According to https://www.mathworks.com/help/signal/ref/decimate.html, the Chebyshev filter order needs to be automatically reduced when the distortion is too large.

Mike Miller <mtmiller>
Group Member
Tue 20 Apr 2021 09:26:02 PM UTC, original submission:  

...\packages\signal-1.4.1\decimate.m

decimate(rand(1e4,1),1e3)
ans [Matlab 2016a]=
    0.5761
    0.4891
    0.4910
    0.5070
    0.5118
    0.4927
    0.4988
    0.5104
    0.5027
    0.5145

ans [Octave 6.2]=
  -6.7591e+108
  -3.6381e+102
   -1.9676e+96
   -8.4446e+89
   -4.0507e+83
   -2.1474e+77
   -8.1876e+70
   -3.5228e+64
   -1.7350e+58
   -8.8927e+51

Does not happen with ratio = 1e2, but maybe the use case is not so significant...
regards,
Paul Netsaver

Paul Netsaver <netsaver>

 

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

Attach Files:
   
   
Comment:
   

No files currently attached

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -email is unavailable- added by pantxo (Updated the item)
  • -email is unavailable- added by netsaver (Submitted the item)
  •  

    There are 0 votes so far. Votes easily highlight which items people would like to see resolved in priority, independently of the priority of the item set by tracker managers.

    Only group members can vote.

     

    Follow 6 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2021-04-21 mtmiller Summary[octave forge] (signal): decimate function outputs divergent numbers [octave forge] (signal) decimate function outputs divergent numbers
    2021-04-21 mtmiller Item GroupIncorrect Result Inaccurate Result
        Release6.2.0 dev
    2021-04-20 pantxo StatusNone Confirmed
        Operating SystemMicrosoft Windows Any
        Summarydecimate function outputs divergent numbers [octave forge] (signal): decimate function outputs divergent numbers

    Back to the top

    Powered by Savane 3.13-4448.
    Corresponding source code