...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::logical_not
// In header: <boost/accumulators/numeric/functional.hpp> template<typename Arg, typename Tag = typename tag<Arg>::type> struct logical_not : public boost::numeric::functional::logical_not_base< Arg, void > { };