...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::tag<std::valarray< T >>
// In header: <boost/accumulators/numeric/functional/valarray.hpp> template<typename T> struct tag<std::valarray< T >> { // types typedef std_valarray_tag type; };