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boost::accumulators::impl::weighted_tail_quantile_impl — Tail quantile estimation based on order statistics of weighted samples (for both left and right tails)
// In header: <boost/accumulators/statistics/weighted_tail_quantile.hpp> template<typename Sample, typename Weight, typename LeftRight> struct weighted_tail_quantile_impl : public accumulator_base { // types typedef numeric::functional::fdiv< Weight, std::size_t >::result_type float_type; typedef Sample result_type; // construct/copy/destruct weighted_tail_quantile_impl(dont_care); // public member functions template<typename Args> result_type result(Args const &) const; };
An estimator of tail quantiles with level based on order statistics of weighted samples are given by (left tail) and (right tail), where \f[ \lambda = \inf\left\{ l \left| \frac{1}{\bar{w}_n}\sum_{i=1}^{l} w_i \geq \alpha \right. \right\} \f] and \f[ \rho = \sup\left\{ r \left| \frac{1}{\bar{w}_n}\sum_{i=r}^{n} w_i \geq (1 - \alpha) \right. \right\}, \f] being the number of samples and the sum of all weights.