Dear R users... I made the R-code for this double summation computation http://www.nabble.com/file/p19213463/doublesum.jpg ------------------------------------------------- Here is my code.. sum(sapply(1:m, function(k){sum(sapply(1:m, function(j){x[k]*x[j]*dnorm((mu[j]+mu[k])/sqrt(sig[k]+sig[j]))/sqrt(sig[k]+sig[j])}))})) ------------------------------------------------- In fact, this is a part of optimization. I think if it is changed more efficiently, then the running time could be reduced. How could I change this to more efficient one? Any suggestion will be greatly appreciated. Kathryn Lord -- View this message in context: http://www.nabble.com/more-efficient-double-sum-computation-...-tp19213463p19213463.html Sent from the R help mailing list archive at Nabble.com.