// sample reduction function for a sum
T sum_reduce(T a, T b) {
  return (b + a);
}

T vect_scalar_sum(vector<T> v) {
  T sum;

  sum.reset(); // i.e., sum = 0

  for (int i=0; i < v.length(); i++) {
    sum = sum_reduce(v[i], sum);
  }

  return sum;
}