function Y=hankel(X,Z)
%HANKEL (overloaded)

% Author Johan L鰂berg 
% $Id: hankel.m,v 1.2 2004/07/01 11:17:10 johanl Exp $  

if nargin>1
   error('Too many input arguments. Only one input supported')
else
   Y = X;
   n = X.n;
   m = X.m;
   temp = sparse(hankel(reshape(X.basis(:,1),n,m)));
   Y.basis = temp(:);   
   for i = 2:length(X.lmi_variables)+1
      temp = sparse(hankel(reshape(X.basis(:,i),n,m)));
      Y.basis(:,i) = temp(:);
   end   
   Y.n = size(temp,1);
   Y.m = size(temp,2);
end

return

if nargin>1
  error('Too many input arguments. Only one input supported')
else
  Y = X;
  Y.basis = [];
  n = X.n;
  m = X.m;
  
  for i = 2:length(X.lmi_variables)+1
    temp = sparse(hankel(reshape(X.basis(:,i),n,m)));
    Y.basis(:,i) = temp(:);
  end   
  Y.n = size(temp,1);
  Y.m = size(temp,2);
end