[Octave-bug-tracker] [bug #63052] [octave forge] (control) Inverse operation with transfer function variables resulting in wrong results

[Doug Stewart]

Follow-up Comment #12, bug #63052 (project octave):

This is definitely A control pkg issue, not a version of octave.


The Real issue is:
1)  some round off errors in a FORTRAN library
     which I can apply my eps hack to, to lessen the effect, of
     the round off errors.
2) the method that the OP used looks correct in text books, 
    but is very susceptible to round off errors.

The normal way to do this is using:
[num,den] =ss2tf (A,B,C,D);
FT2 = tf (num,den) 

always gives the correct answer. So I am hesitant to make any changes.

I tried many other examples and they worked ok. The OP just tried one that has
round off errors

Any way the changes would only be in the control pkg
  


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