STRUCT (3)

NAME
boost::accumulators::impl::lazy_weighted_variance_impl - Lazy calculation of variance of weighted samples.

SYNOPSIS

// In header: <boost/accumulators/statistics/weighted_variance.hpp>
template<typename Sample, typename Weight, typename MeanFeature>
struct lazy_weighted_variance_impl {
  // types
  typedef numeric::functional::multiplies< Sample, Weight >::result_type       weighted_sample;
  typedef numeric::functional::average< weighted_sample, Weight >::result_type result_type;
  // construct/copy/destruct
  lazy_weighted_variance_impl(dont_care);
  // public member functions
  template<typename Args> result_type result(Args const &) const;
};

DESCRIPTION

The default implementation of the variance of weighted samples is based on the second moment [1][IMAGE][2] [$ (weighted_moment<2>) and the mean [3][IMAGE][4] [$ (weighted_mean): Equation 1.42.  [5].sp .RS 4 [IMAGE][6] \[ \hat{\sigma}_n^2 = \widehat{m}_n^{(2)}-\hat{\mu}_n^2, \] .RE where [7][IMAGE][8] [$n$] is the number of samples.

  lazy_weighted_variance_impl public construct/copy/destruct

    1.

    lazy_weighted_variance_impl(dont_care);

  lazy_weighted_variance_impl public member functions

    1.

    template<typename Args> result_type result(Args const & args) const;