Re: Octave Bug

[A S Hodel]

This is true.  When I wrote the octave controls toolbox we didn't
have cell arrays (that was about 8 years ago), so I went with
scalar systems only.  It would be quite a big change to add cell arrays
to allow for MIMO tf and zp forms.

That said, it would be nice to do so.  While being "like MATLAB" is not
a paramount goal, I think that it would be valuable to define a system 
data
type so that we could write things like

mysys = ss(A,B,C,D) + tf(num,den)


On Sep 15, 2004, at 2:20 AM, Gabriele Pannocchia wrote:

>  Hi,
>
>  This is not an Octave bug. As far as I know, tf2sys(num,den) is
>  implemented for scalar systems only. Therefore (num,den) must be
>  vectors of coefficients. In your example, "a" is matrix and "b" is a
>  vector.
>
>  Cheers,
>         Gabriele
>
>  PS. Currently, the use of tf2sys is depracated. tf() is the current
>  function to use.
>
> > I just tried running an example from the Octave
> > control systems page and it crashed.  The following is
> > what I had:
> >
> > octave:1> a = [1 -2; -1.1 -2.1];
> > octave:2> b = [1; 2; 1];
> > octave:3> sys = tf2sys(a, b)
> > error: num (2x2) and den (3x1) must be vectors
> > error: evaluating if command near line 69, column 3
> > error: called from `tf2sys' in file
> > `/sw/share/octave/2.1.53/m/control/system/tf2sys.m'
> > error: evaluating assignment expression near line 3,
> > column 5
> >
> > I've tried numerous other examples from that same
> > section and had similar results.
> >
> > I'm using Octave 2.1.53 for Darwin, which is the
> > current stable version on Fink.
> >
> > Please advise.  Thanks.
> >
> > B. M. Jatzeck
> >
> >
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Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
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