armac Scilab description of an armax process

## Syntax

    ar = armac(a, b, d, ny, nu, sig)

## Arguments

a=[Id,a1,..,a_r]

  is a matrix of size (ny,r*ny)

b=[b0,.....,b_s]

  is a matrix of size (ny,(s+1)*nu)

d=[Id,d1,..,d_p]

  is a matrix of size (ny,p*ny);

ny

  dimension of the output y

nu

  dimension of the output u

sig

  a matrix of size (ny,ny)

## Description

This function creates a description as a tlist of an ARMAX process

`ar` is defined by

    ar=tlist(['ar','a','b','d','ny','nu','sig'],a,b,d,ny,nu,sig);

and thus the coefficients of `ar` can be retrieved by e.g. `ar('a')` .

## Examples

    a=[1,-2.851,2.717,-0.865].*.eye(2,2)
    b=[0,1,1,1].*.[1;1];
    d=[1,0.7,0.2].*.eye(2,2);
    sig=eye(2,2);
    ar=armac(a,b,d,2,1,sig)
    // extract polynomial matrices from ar representation
    [A,B,D]=arma2p(ar);

## See also

- arma
- armax
- armax1
- arsimul
- arma2p
- tlist