order.m

A Matlab toolbox for exact linear time-invariant system identification is presented. The emphasis is

% ORDER - order delection from the singular values.
%
% n = order(s,tol)
% 
% S   - vector of singular values
% TOL - tolerance for order selection, default 1e-7
%   If TOL < 0, the SVs are plotted and an input is asked.
% N   - order

function n = order(s,tol)

TOL = 1e-7; % default value for the tolerance

if nargin < 2 | isempty(tol)
  tol = TOL;
end

if tol > 0
  n = sum(s > tol);
else
  bar(s); 
  title('singular values'), xlabel('i'), ylabel('s_i'),
  n = input('Choose the order = ');
end