% correl(x,y,N)

function rxy = corrph(x,y,S)

L = lge(x);
N = L-S;

if (N == 0)
  error('N = 0 !');
end;

for s=0:S-1,
%rxy(s)=sum(x(S-s+1:L-s+1).*y(S:L))^2/(sum(x(S-s+1:L-s+1).^2)*sum(y(S:L).^2));
%rxy(s)=abs(sum(x(S-s+1:L-s+1).*y(S:L)))/(sum(abs(x(S-s+1:L-s+1).*y(S:L)))+0.0001);
rxy(s+1)=sum(x(1:L-S).*y(1+s:L-S+s))/(sum(abs(x(1:L-S).*y(1+s:L-S+s)))+0.001);
%rxy(s+1)=sum((x(1:L-S).^2).*(y(1+s:L-S+s).^2))/(sum(x(1:L-S).^2 + y(1+s:L-S+s).^2) +0.001);
end;