abcd
====

state-space matrices



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


::

    [A,B,C,D]=abcd(sl)




Arguments
~~~~~~~~~

:sl linear system ( `syslin` list) in state-space or transfer form
: :A,B,C,D real matrices of appropriate dimensions
:



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

returns the `A,B,C,D` matrices from a linear system `Sl`.

Utility function. For transfer matrices `Sl` is converted into state-
space form by `tf2ss`.

The matrices `A,B,C,D` are the elements `2` to `5` of the `syslin`
list `Sl`, i.e. `[A,B,C,D] = Sl(2:5)` .



Examples
~~~~~~~~


::

    A=`diag`_([1,2,3]);B=[1;1;1];C=[2,2,2];
    sys=`syslin`_('c',A,B,C);
    sys("A")
    sys("C")
    [A1,B1,C1,D1]=abcd(sys);
    A1
    systf=`ss2tf`_(sys);
    [a,b,c,d]=abcd(systf)
    `spec`_(a)
    c*b-C*B
    c*a*b-C*A*B




See Also
~~~~~~~~


+ `syslin`_ linear system definition
+ `ssrand`_ random system generator


.. _ssrand: ssrand.html
.. _syslin: syslin.html