contrss controllable part

## Syntax

                slc = contrss(sl)
                slc = contrss(sl, tol)

## Arguments

sl

  linear system (`syslin` list)

tol

  is a threshold for controllability (see `contr`). default value is `sqrt(%eps)`.

## Description

returns the controllable part of the linear system `sl = (A,B,C,D)` in state-space form.

## Examples

    A=[1,1;0,2];B=[1;0];C=[1,1];sl=syslin('c',A,B,C);  //Non minimal
    slc=contrss(sl);
    sl1=ss2tf(sl);sl2=ss2tf(slc);      //Compare sl1 and sl2

## See also

- cont_mat
- ctr_gram
- cont_frm
- contr