...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::impl::density_impl — Histogram density estimator.
// In header: <boost/accumulators/statistics/density.hpp> template<typename Sample> struct density_impl { // types typedef numeric::functional::average< Sample, std::size_t >::result_type float_type; typedef std::vector< std::pair< float_type, float_type > > histogram_type; typedef std::vector< float_type > array_type; typedef iterator_range< typename histogram_type::iterator > result_type; // construct/copy/destruct template<typename Args> density_impl(Args const &); // public member functions template<typename Args> void operator()(Args const &); template<typename Args> result_type result(Args const &) const; };
The histogram density estimator returns a histogram of the sample distribution. The positions and sizes of the bins are determined using a specifiable number of cached samples (cache_size). The range between the minimum and the maximum of the cached samples is subdivided into a specifiable number of bins (num_bins) of same size. Additionally, an under- and an overflow bin is added to capture future under- and overflow samples. Once the bins are determined, the cached samples and all subsequent samples are added to the correct bins. At the end, a range of std::pair is return, where each pair contains the position of the bin (lower bound) and the samples count (normalized with the total number of samples).