Re: sys2tf seems broken in 2.1.38

[John W. Eaton]

On  1-Nov-2002, Nicholas Piper <address@hidden> wrote:

| On Fri, 01 Nov 2002, John W. Eaton wrote:
| 
| > On  1-Nov-2002, Nicholas Piper <address@hidden> wrote:
| 
| > | step(sys) -> Error
| > | sysout(sys,'tf') -> Error
| > | sysout(sys) -> Works
| 
| > This seems to work correctly with my current sources.
| 
| I've just built from CVS (checked out about half an hour ago), and it
| still fails.
| 
| octave:1> k=3;b=2;f=9.81;m=10; 
| octave:2> A=[0 1; -k/m -b/m];B=[0;1/m];C=[1 0];D=[0]; 
| octave:3> sys = ss2sys(A,B,C,D); 
| octave:4>  step(sys)
|  ** On entry to DGESVD parameter number 13 had an illegal value

What system are you using?  What lapack do you have?  If you are using
some vendor-supplied version of lapack, it could be out of date
compared to what Octave needs.  Octave assumes that you have the
latest (or something like ATLAS that is based on the latest) version
of lapack.  I think in this particular case, Octave is calling DGESVD
once with LWORK = -1 and expecting it to return the proper length of
the work array.  So it looks like your version of lapack doesn't
handle that.

| Which I don't quite understand. I presume your current sources ==
| current CVS ?

Close enough, yes.

jwe



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