Re: question on control-1.0.11 package

[Huub]

On 4/24/10 3:40 PM, Francesco Potortì wrote:
> > Edit: by another calculation using tf2zp the difference between Octave
> > and Matlab shows again. Octave returns for k = 0, while Matlab returns
> > for k = 100.
>
> I don't think that it is possible to understand what is going on without
> code.  Can you provide an example?

Sure.

num = [0 0 0 100];
den = [1 10.1 101 0];
[z,p,k] = tf2zp(num, den);

Octave gives:

octave-3.2.3:7> [z,p,k] = tf2zp(num, den)
z = [](0x1)
p =

  -5.05000 + 8.68893i
  -5.05000 - 8.68893i
   0.00000 + 0.00000i

k = 0

Matlab gives:

>> [z,p,k] = tf2zp(num, den)

z =

   Empty matrix: 0-by-1


p =

        0
  -5.0500 + 8.6889i
  -5.0500 - 8.6889i


k =

   100