Z=Matrix_z(z,N,M)

% Description: create a Vandermonde matrix [z1^0 ...    zN^0; 
%                                           z1^1 ...    zN^1;
%                                           z1^{M-1}... zN^{M-1}]

% Hien M. Nguyen, ECE, UIUC, Mar 29, 2005
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function Z=Matrix_z(z,N,M)
% z is a row vector

tg=[z zeros(1,M+1-N)].';
Z=rot90(vander(tg));
% truncate columns of vander matrix to have correct Z
Z=Z(:,1:N);