Hi, I want to calculate expected likelihood over a 2D discrete distribution, something like \sum_k \sum_l p_{kl} L(v_k, v_l) It is trivial to write a cycle like for(k in 1:K) for(l in 1:L) sum <- sum + p[k,l]*L(v[k], v[l]) But is there a more clever way for R? Best wishes, Ott