%The script calculate the entropy point estimation for 1D data by
%Kozachenko-Leonenko method.
%
%input - empiric data
%E - entropy point estimation
function E = EntropyEstimationKL(input)
    q = 1; %dimension
    n = length(input);   
    
    %distance to the nearest neighbour
    input = sort(input);
    r = zeros(1,n);
    r(1) = input(2)-input(1);
    for k = 2:n-1
        r(k) = min([input(k+1) - input(k),input(k) - input(k-1)]);        
    end
    r(n) = input(n)-input(n-1);
    
    %estimation
    const = (n-1)*(pi^(q/2))/gamma(1+q/2);
    E = (q/n)*sum(log(r))+log(const)+0.5772156649;