function [en]=norms(x,k)

n = length(x);
sum = zeros(k,1);
for j=1:k
    sum(j) = x(j)*x(j);
end
for i=2:n/k
    for j=1:k
        sum(j) = sum(j) + x(k*(i-1)+j)*x(k*(i-1)+j);
    end
end
ns = 0;
for j=1:k
    ns = ns + sum(j);
end
en = ns^(1/2);