Re: Request for Matlab output

[Steph Bredenhann]

See results from 2015b on Ubuntu x64 below

On 29/10/2015 13:25, Lukas Reichlin wrote:
> Dear Octave community,
>
> In order to improve error handling in the control package, I would like to know 
> what Matlab’s output/error message looks like for each of the following three 
> lines of code:
>
> dss (1, 2, 3, 4, 0)
ans =

  a =
       x1
   x1   1

  b =
       u1
   x1   2

  c =
       x1
   y1   3

  d =
       u1
   y1   4

  e =
       x1
   x1   0

Continuous-time state-space model.

> feedback (tf (1), tf (-1))
Error using InputOutputModel/feedback (line 137)
Feedback interconnection has infinite gain at all frequencies due to 
singular algebraic
loops.

Error in untitled (line 5)
feedback (tf (1), tf (-1))

> feedback (ss (1), ss (-1))
Warning: The closed-loop model may be improper because of singular 
algebraic loops.
> In InputOutputModel/feedback (line 134)
  In untitled (line 5)

ans =

  d =
        u1
   y1  NaN

Static gain.

> Could someone with access to Matlab and its Control System Toolbox please send 
> me the resulting text output?
>
> Thanks in advance,
> Lukas