function [a,b] = DLS(y)
%
% coefficients for Least Squares with Discrete Fourier Basis
%
n = length(y);
y = y(:);
c = ifft(y);
m = n/2;
L = 2*(1:m);
c(L) = - c(L);
a = real(c(1:m+1));
b = 2*imag(c(2:m));
a(2:m) = 2 * a(2:m);

