systmat system matrix

## Syntax

    Sm = systmat(Sl)

## Arguments

Sl

  linear system (`syslin` list) or descriptor system

Sm

  matrix pencil

## Description

System matrix of the linear system `Sl` (`syslin` list) in state-space form (utility function).

    Sm = [-sI + A   B;
         [    C     D]

For a descriptor system (`Sl=list('des',A,B,C,D,E)`), `systmat` returns:

    Sm = [-sE + A   B;
         [    C     D]

## See also

- ss2des
- sm2des
- sm2ss