...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::accumulators::tag::lazy_variance
// In header: <boost/accumulators/statistics/variance.hpp> struct lazy_variance : public boost::accumulators::depends_on< moment< 2 >, mean > { };