[Octave-bug-tracker] [bug #31165] error: inv: wrong type argument "class"

[Lukas Reichlin]

URL:
  <http://savannah.gnu.org/bugs/?31165>

                 Summary: error: inv: wrong type argument "class"
                 Project: GNU Octave
            Submitted by: paramaniac
            Submitted on: Thu 30 Sep 2010 03:49:03 AM GMT
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.3.52
        Operating System: Mac OS

    _______________________________________________________

Details:

Dear Octave Community

I noticed a problem with "inv" from Octave 3.3.52 and
"control/inst/@lti/inv.m" [1]. Interestingly, the first attempt (see examples
below) succeeds, while subsequent calls fail (inv: wrong type argument
`class'). This problem doesn't occur on Octave 3.2.4. I'm using MacOSX 10.6.4
and an up-to-date MacPorts installation.

Thanks in advance for your help and best regards,
Lukas


[1]
control, SVN Revision 7781. "pkg install" takes about 90 seconds. First
public release planned on arrival of Octave 3.4.
http://octave.svn.sourceforge.net/viewvc/octave/trunk/octave-forge/main/control/


IMPLEMENTATION NOTES:
* "State-Space" (@ss/ss.m) and "Transfer Function" (@tf/tf.m) models are both
inherited from class "Linear Time Invariant" (@lti/lti.m).
* Overloaded operators like "inv" are located inside control/inst/@lti.
* @lti/inv.m is also called by @lti/mrdivide.m (used in example 1)


## =======================
## Example 1
## =======================

GNU Octave, version 3.3.52
Copyright (C) 2010 John W. Eaton and others.
This is free software; see the source code for copying conditions.
There is ABSOLUTELY NO WARRANTY; not even for MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  For details, type `warranty'.

Octave was configured for "x86_64-apple-darwin10.4.0".

Additional information about Octave is available at http://www.octave.org.

Please contribute if you find this software useful.
For more information, visit http://www.octave.org/help-wanted.html

Read http://www.octave.org/bugs.html to learn how to submit bug reports.

For information about changes from previous versions, type `news'.




octave:1> test_control
PASSES 66 out of 66 tests
PASSES 2 out of 2 tests
PASSES 2 out of 2 tests
PASSES 6 out of 6 tests
PASSES 3 out of 3 tests
PASSES 3 out of 3 tests
PASSES 3 out of 3 tests
PASSES 2 out of 2 tests
PASSES 5 out of 5 tests
PASSES 4 out of 4 tests
PASSES 3 out of 3 tests
PASSES 4 out of 4 tests
PASSES 1 out of 1 tests
PASSES 2 out of 2 tests
PASSES 2 out of 2 tests
PASSES 2 out of 2 tests
PASSES 1 out of 1 tests
PASSES 1 out of 1 tests
PASSES 16 out of 16 tests
octave:2> test_control
 ***** shared a
s = tf ("s");
G = (s+1)*s*5/(s+1)/(s^2+s+1);
a = G(1,1).num{1,1}(1);
!!!!! test failed
inv: wrong type argument `class'
shared variables {
 a = [](octave:3> test_control
octave:4> test_control
octave:5> 

BTW: Note the "forgotten" output after command 3 and 4. I've never seen such
problems in Octave 3.2.x 


## =======================
## Example 2
## =======================

octave:1> sys = ss (-1, 1, 1, 0)

sys.a =
      x1
  x1  -1

sys.b =
      u1
  x1   1

sys.c =
      x1
  y1   1

sys.d =
      u1
  y1   0

Continuous-time model.
octave:2> sysi = inv (sys)

sysi.e =
      x1  x2
  x1   1   0
  x2   0   0

sysi.a =
      x1  x2
  x1  -1   1
  x2   1   0

sysi.b =
      u1
  x1   0
  x2  -1

sysi.c =
      x1  x2
  y1   0   1

sysi.d =
      u1
  y1   0

Continuous-time model.
octave:3> sysi = inv (sys)
error: inv: wrong type argument `class'
octave:3> which inv
`inv' is a function from the file
/opt/local/libexec/octave/3.3.52/oct/x86_64-apple-darwin10.4.0/inv.oct
octave:4> sysi = inv (sys)
error: inv: wrong type argument `class'
octave:4> sysi = inv (sys)
error: inv: wrong type argument `class'
octave:4> 

## =======================





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