what about changing your code to the following? any noticeable speed changes? size_t size = data.size(); for (size_t i = 1; i != size; ++i) { data[i] += data

what about changing your code to the following? any noticeable speed changes? size_t size = data.size(); for (size_t i = 1; i != size; ++i) { data[i] += data[i - 1] ; }