//From htpp://www.richelbilderbeek.nl/CppGetCumulativeHistogram.htm
template <class T> const std::vector<T> GetCumulativeHistogram(const std::vector<T>& histogram)
{
  std::vector<T> v(histogram.begin(),histogram.end() );
  const int size = v.size();
  for (int i=1; i!=size; ++i)
  {
    v[i] += v[i-1];
  }
  return v;
}