[Octave-bug-tracker] [bug #44949] rlocus gives discontinuous data

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?44949>

                 Summary: rlocus gives discontinuous data
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Tue 28 Apr 2015 07:10:49 PM UTC
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Sebastien
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.8.1
        Operating System: GNU/Linux

    _______________________________________________________

Details:

When running the following program


clear all

%get some system
s = tf('s');
G = 1/(s*(s+3)*(s+6));

%get root locust data
[rldata, k_list] = rlocus(G, 0.01, 0, 40);

%define some controler
Z_CI=4.52921067560045;
G_pd = (s+Z_CI);

%get root locust data
[rldata_pd k_list_pd] = rlocus(G_pd*G, 0.01, 0, 40);


The data contained in rldata_pd is scrambled such that starting at index 2628,
row 1 and 2 are inverted, causing a discontinuous vector. The result of 


%the plot is discontinuous
rldata_pd(1,2627:2628)
rldata_pd(2,2627:2628)


show that behaviour and displays


ans =

  -4.91792703087913 + 0.00000000000000i  -2.04110517684489 +
4.47493066843290i

ans =

  -2.04103648456044 + 4.47385708453766i  -4.91778964631022 +
0.00000000000000i


This can also be replicated when a single argument is given to rlocus, but the
location of the crossover point will be different.



    _______________________________________________________

File Attachments:


-------------------------------------------------------
Date: Tue 28 Apr 2015 07:10:49 PM UTC  Name: mwe.m  Size: 545B   By: None

<http://savannah.gnu.org/bugs/download.php?file_id=33828>

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?44949>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/