zeropen
=======

zero pencil



Calling Sequence
~~~~~~~~~~~~~~~~


::

    [Z,U]=zeropen(Sl)




Arguments
~~~~~~~~~

:Sl a linear system ( `syslin` list in state-space form `[A,B,C,D]`)
: :Z matrix pencil `Z=s*E-A`
: :U square orthogonal matrix
:



Description
~~~~~~~~~~~

`Z= sE - F` is the zero pencil of the linear system `Sl` with matrices
`[A,B,C,D]`. Utility function.

With `U` row compression of `[B;D]` i.e, `U*[B;D]=[0;*]`; one has:


::

    U*[-sI+A |B;   [ Z |0;      
          C  |D] = [ * |*]


The zeros of `Z` are the zeros of `Sl`.



See Also
~~~~~~~~


+ `systmat`_ system matrix
+ `kroneck`_ Kronecker form of matrix pencil


.. _kroneck: kroneck.html
.. _systmat: systmat.html