dcf double coprime factorization

## Syntax

                [N,M, X,Y, NT,MT, XT,YT] = dcf(G)
                [N,M, X,Y, NT,MT, XT,YT] = dcf(G, polf, polc)
                [N,M, X,Y, NT,MT, XT,YT] = dcf(G, polf, polc, tol)

## Arguments

G

  `syslin` list (continuous-time linear system)

polf, polc

  respectively the poles of `XT` and `YT` and the poles of `N` and `M` (default values =`-1`).

tol

  real threshold for detecting stable poles (default value `100*%eps`).

N,M,XT,YT,NT,MT,X,Y

  linear systems represented by `syslin` lists

## Description

returns eight stable systems `(N,M,X,Y,NT,MT,XT,YT)` for the doubly coprime factorization

`G` must be stabilizable and detectable.

## See also

- copfac