/////////////////////////////////////////////////////////////////////////////// // mean.hpp // // Copyright 2005 Eric Niebler. Distributed under the Boost // Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) #ifndef BOOST_ACCUMULATORS_STATISTICS_MEAN_HPP_EAN_28_10_2005 #define BOOST_ACCUMULATORS_STATISTICS_MEAN_HPP_EAN_28_10_2005 #include <boost/mpl/placeholders.hpp> #include <boost/accumulators/framework/accumulator_base.hpp> #include <boost/accumulators/framework/extractor.hpp> #include <boost/accumulators/numeric/functional.hpp> #include <boost/accumulators/framework/parameters/sample.hpp> #include <boost/accumulators/framework/depends_on.hpp> #include <boost/accumulators/statistics_fwd.hpp> #include <boost/accumulators/statistics/count.hpp> #include <boost/accumulators/statistics/sum.hpp> namespace boost { namespace accumulators { namespace impl { /////////////////////////////////////////////////////////////////////////////// // mean_impl // lazy, by default template<typename Sample, typename SumFeature> struct mean_impl : accumulator_base { // for boost::result_of typedef typename numeric::functional::fdiv<Sample, std::size_t>::result_type result_type; mean_impl(dont_care) {} template<typename Args> result_type result(Args const &args) const { extractor<SumFeature> sum; return numeric::fdiv(sum(args), count(args)); } // serialization is done by accumulators it depends on template<class Archive> void serialize(Archive & ar, const unsigned int file_version) {} }; template<typename Sample, typename Tag> struct immediate_mean_impl : accumulator_base { // for boost::result_of typedef typename numeric::functional::fdiv<Sample, std::size_t>::result_type result_type; template<typename Args> immediate_mean_impl(Args const &args) : mean(numeric::fdiv(args[sample | Sample()], numeric::one<std::size_t>::value)) { } template<typename Args> void operator ()(Args const &args) { std::size_t cnt = count(args); this->mean = numeric::fdiv( (this->mean * (cnt - 1)) + args[parameter::keyword<Tag>::get()] , cnt ); } result_type result(dont_care) const { return this->mean; } template<class Archive> void serialize(Archive & ar, const unsigned int file_version) { ar & mean; } private: result_type mean; }; } // namespace impl /////////////////////////////////////////////////////////////////////////////// // tag::mean // tag::immediate_mean // tag::mean_of_weights // tag::immediate_mean_of_weights // tag::mean_of_variates // tag::immediate_mean_of_variates // namespace tag { struct mean : depends_on<count, sum> { /// INTERNAL ONLY /// typedef accumulators::impl::mean_impl<mpl::_1, sum> impl; }; struct immediate_mean : depends_on<count> { /// INTERNAL ONLY /// typedef accumulators::impl::immediate_mean_impl<mpl::_1, tag::sample> impl; }; struct mean_of_weights : depends_on<count, sum_of_weights> { typedef mpl::true_ is_weight_accumulator; /// INTERNAL ONLY /// typedef accumulators::impl::mean_impl<mpl::_2, sum_of_weights> impl; }; struct immediate_mean_of_weights : depends_on<count> { typedef mpl::true_ is_weight_accumulator; /// INTERNAL ONLY /// typedef accumulators::impl::immediate_mean_impl<mpl::_2, tag::weight> impl; }; template<typename VariateType, typename VariateTag> struct mean_of_variates : depends_on<count, sum_of_variates<VariateType, VariateTag> > { /// INTERNAL ONLY /// typedef mpl::always<accumulators::impl::mean_impl<VariateType, sum_of_variates<VariateType, VariateTag> > > impl; }; template<typename VariateType, typename VariateTag> struct immediate_mean_of_variates : depends_on<count> { /// INTERNAL ONLY /// typedef mpl::always<accumulators::impl::immediate_mean_impl<VariateType, VariateTag> > impl; }; } /////////////////////////////////////////////////////////////////////////////// // extract::mean // extract::mean_of_weights // extract::mean_of_variates // namespace extract { extractor<tag::mean> const mean = {}; extractor<tag::mean_of_weights> const mean_of_weights = {}; BOOST_ACCUMULATORS_DEFINE_EXTRACTOR(tag, mean_of_variates, (typename)(typename)) BOOST_ACCUMULATORS_IGNORE_GLOBAL(mean) BOOST_ACCUMULATORS_IGNORE_GLOBAL(mean_of_weights) } using extract::mean; using extract::mean_of_weights; using extract::mean_of_variates; // mean(lazy) -> mean template<> struct as_feature<tag::mean(lazy)> { typedef tag::mean type; }; // mean(immediate) -> immediate_mean template<> struct as_feature<tag::mean(immediate)> { typedef tag::immediate_mean type; }; // mean_of_weights(lazy) -> mean_of_weights template<> struct as_feature<tag::mean_of_weights(lazy)> { typedef tag::mean_of_weights type; }; // mean_of_weights(immediate) -> immediate_mean_of_weights template<> struct as_feature<tag::mean_of_weights(immediate)> { typedef tag::immediate_mean_of_weights type; }; // mean_of_variates<VariateType, VariateTag>(lazy) -> mean_of_variates<VariateType, VariateTag> template<typename VariateType, typename VariateTag> struct as_feature<tag::mean_of_variates<VariateType, VariateTag>(lazy)> { typedef tag::mean_of_variates<VariateType, VariateTag> type; }; // mean_of_variates<VariateType, VariateTag>(immediate) -> immediate_mean_of_variates<VariateType, VariateTag> template<typename VariateType, typename VariateTag> struct as_feature<tag::mean_of_variates<VariateType, VariateTag>(immediate)> { typedef tag::immediate_mean_of_variates<VariateType, VariateTag> type; }; // for the purposes of feature-based dependency resolution, // immediate_mean provides the same feature as mean template<> struct feature_of<tag::immediate_mean> : feature_of<tag::mean> { }; // for the purposes of feature-based dependency resolution, // immediate_mean provides the same feature as mean template<> struct feature_of<tag::immediate_mean_of_weights> : feature_of<tag::mean_of_weights> { }; // for the purposes of feature-based dependency resolution, // immediate_mean provides the same feature as mean template<typename VariateType, typename VariateTag> struct feature_of<tag::immediate_mean_of_variates<VariateType, VariateTag> > : feature_of<tag::mean_of_variates<VariateType, VariateTag> > { }; // So that mean can be automatically substituted with // weighted_mean when the weight parameter is non-void. template<> struct as_weighted_feature<tag::mean> { typedef tag::weighted_mean type; }; template<> struct feature_of<tag::weighted_mean> : feature_of<tag::mean> {}; // So that immediate_mean can be automatically substituted with // immediate_weighted_mean when the weight parameter is non-void. template<> struct as_weighted_feature<tag::immediate_mean> { typedef tag::immediate_weighted_mean type; }; template<> struct feature_of<tag::immediate_weighted_mean> : feature_of<tag::immediate_mean> {}; // So that mean_of_weights<> can be automatically substituted with // weighted_mean_of_variates<> when the weight parameter is non-void. template<typename VariateType, typename VariateTag> struct as_weighted_feature<tag::mean_of_variates<VariateType, VariateTag> > { typedef tag::weighted_mean_of_variates<VariateType, VariateTag> type; }; template<typename VariateType, typename VariateTag> struct feature_of<tag::weighted_mean_of_variates<VariateType, VariateTag> > : feature_of<tag::mean_of_variates<VariateType, VariateTag> > { }; // So that immediate_mean_of_weights<> can be automatically substituted with // immediate_weighted_mean_of_variates<> when the weight parameter is non-void. template<typename VariateType, typename VariateTag> struct as_weighted_feature<tag::immediate_mean_of_variates<VariateType, VariateTag> > { typedef tag::immediate_weighted_mean_of_variates<VariateType, VariateTag> type; }; template<typename VariateType, typename VariateTag> struct feature_of<tag::immediate_weighted_mean_of_variates<VariateType, VariateTag> > : feature_of<tag::immediate_mean_of_variates<VariateType, VariateTag> > { }; //////////////////////////////////////////////////////////////////////////// //// droppable_accumulator<mean_impl> //// need to specialize droppable lazy mean to cache the result at the //// point the accumulator is dropped. ///// INTERNAL ONLY ///// //template<typename Sample, typename SumFeature> //struct droppable_accumulator<impl::mean_impl<Sample, SumFeature> > // : droppable_accumulator_base< // with_cached_result<impl::mean_impl<Sample, SumFeature> > // > //{ // template<typename Args> // droppable_accumulator(Args const &args) // : droppable_accumulator::base(args) // { // } //}; }} // namespace boost::accumulators #endif