for the sake of language geekdom, it would be done in J something like this: - +/ p * ^. p where p is the array. you can even remove the duplication of the

for the sake of language geekdom, it would be done in J something like this: - +/ p * ^. p where p is the array. you can even remove the duplication of the array with a so-called hook: - +/ (* ^.) p