function [corr,corrcoeff,media,varianza] = correlazione(x,k)
%function [corr,corrcoeff,media,varianza] = correlazione(x,k)
%x: matrice processo aleatorio
%k: elementi correlazione e coefficiente di correlazione
media=mean(x);
varianza=var(x);
for m=1:size(x,2)-k
    %if rem(m,500)==0, m, end
    for n=0:size(x,2)-m-1 
        corr(m,n+1)=mean(x(:,m).*x(:,n+m));
        corrcoeff(m,n+1)=(corr(m,n+1)-media(m)*media(n+m))/(varianza(m)*varianza(n+m))^.5;
    end 
end
end