...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::numeric::functional::multiply_and_promote_to_double
// In header: <boost/accumulators/statistics/weighted_tail_variate_means.hpp> template<typename T, typename U> struct multiply_and_promote_to_double : public functional::multiplies<T, double const> { };