Function File: renyi_entropy (alpha, P)

Compute the Renyi entropy of order alpha, for the given probability distribution P.

Halpha(P(x)) = log\sum_i(P(x_i)^alpha)/(1-alpha)

special-cases include, when alpha=1, it reduces to regular definition of shannon entropy, and when alpha=0, it reduces to hartley entropy.

                   renyi_entropy(0,[0.2 0.3 0.5])
                   ⇒   ans = 1.0986