sys2zp.m

similer program for matlab

## Copyright (C) 1996, 2000, 2002, 2004, 2005, 2006, 2007
##               Auburn University.  All rights reserved.
##
## This file is part of Octave.
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## -*- texinfo -*-
##@deftypefn {Function File} {[@var{zer}, @var{pol}, @var{k}, @var{tsam}, @var{inname}, @var{outname}] =} sys2zp (@var{sys})
## Extract zero/pole/leading coefficient information from a system data
## structure.
##
## See @command{zp} for parameter descriptions.
##
## @strong{Example}
## @example
## octave:1> sys=ss([1 -2; -1.1,-2.1],[0;1],[1 1]);
## octave:2> [zer,pol,k] = sys2zp(sys)
## zer = 3.0000
## pol =
##   -2.6953
##    1.5953
## k = 1
## @end example
## @end deftypefn

## Author: John Ingram <[e-mail]>
## Created: July 15, 1996

function [zer, pol, k, tsam, inname, outname] = sys2zp (sys)

  if (nargin != 1)
    print_usage ();
  elseif (! isstruct (sys))
    error ("sysconnect: sys must be in system data structure form")
  elseif (! is_siso (sys))
    [n, nz, m, p] = sysdimensions (sys);
    error ("system is not SISO: %d inputs, %d outputs", m, p);
  endif

  ## update zero-pole form
  sys = sysupdate (sys, "zp");

  zer = sys.zer;
  pol = sys.pol;
  k = sys.k;
  tsam    = sysgettsam (sys);
  inname  = sysgetsignals (sys, "in");
  outname = sysgetsignals (sys, "out");

endfunction