[Octave-bug-tracker] [bug #57359] residuez gives an incorrect result for [1 1 1.5 .5], [1 1.5 .5]

[anonymous]

URL:
  <https://savannah.gnu.org/bugs/?57359>

                 Summary: residuez gives an incorrect result for [1 1 1.5
.5],[1 1.5 .5]
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Thu 05 Dec 2019 03:01:35 AM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Andrew Stone
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 5.1.0
        Operating System: GNU/Linux

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Details:

the octave residuez function when run on the transfer function [1 1 1.5 .5],[1
1.5 .5] gives results consistent with the matlab command, except for the K
polynomial (or the FIR part, as octave calls it). In Octave the K polynomial
is [1 0] whereas in matlab it is [0 1]. This is of course, assuming that the F
row vector Octave returns is in the format: f(0)+f(1)z^-1... Working it out on
paper shows the MATLAB answer to be correct, and the Octave answer to be
incorrect.
minimal example:

pkg load signal
[r,p,k] = residuez([1 1 1.5 .5],[1 1.5 .5])

output:

r =

   2
  -1

p =

  -1.00000
  -0.50000

k =

   1   0


expected output (from MATLAB):

r =

   2
  -1

p =

  -1.00000
  -0.50000

k =

   0   1





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