1 /////////////////////////////////////////////////////////////////////////////// 2 // weighted_sum.hpp 3 // 4 // Copyright 2006 Eric Niebler, Olivier Gygi. Distributed under the Boost 5 // Software License, Version 1.0. (See accompanying file 6 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 7 8 #ifndef BOOST_ACCUMULATORS_STATISTICS_WEIGHTED_SUM_HPP_EAN_28_10_2005 9 #define BOOST_ACCUMULATORS_STATISTICS_WEIGHTED_SUM_HPP_EAN_28_10_2005 10 11 #include <boost/mpl/placeholders.hpp> 12 #include <boost/accumulators/framework/accumulator_base.hpp> 13 #include <boost/accumulators/framework/extractor.hpp> 14 #include <boost/accumulators/numeric/functional.hpp> 15 #include <boost/accumulators/framework/parameters/sample.hpp> 16 #include <boost/accumulators/framework/parameters/weight.hpp> 17 #include <boost/accumulators/framework/accumulators/external_accumulator.hpp> 18 #include <boost/accumulators/framework/depends_on.hpp> 19 #include <boost/accumulators/statistics_fwd.hpp> 20 21 namespace boost { namespace accumulators 22 { 23 24 namespace impl 25 { 26 /////////////////////////////////////////////////////////////////////////////// 27 // weighted_sum_impl 28 template<typename Sample, typename Weight, typename Tag> 29 struct weighted_sum_impl 30 : accumulator_base 31 { 32 typedef typename numeric::functional::multiplies<Sample, Weight>::result_type weighted_sample; 33 34 // for boost::result_of 35 typedef weighted_sample result_type; 36 37 template<typename Args> weighted_sum_implboost::accumulators::impl::weighted_sum_impl38 weighted_sum_impl(Args const &args) 39 : weighted_sum_( 40 args[parameter::keyword<Tag>::get() | Sample()] 41 * numeric::one<Weight>::value 42 ) 43 { 44 } 45 46 template<typename Args> operator ()boost::accumulators::impl::weighted_sum_impl47 void operator ()(Args const &args) 48 { 49 // what about overflow? 50 this->weighted_sum_ += args[parameter::keyword<Tag>::get()] * args[weight]; 51 } 52 resultboost::accumulators::impl::weighted_sum_impl53 result_type result(dont_care) const 54 { 55 return this->weighted_sum_; 56 } 57 58 private: 59 60 weighted_sample weighted_sum_; 61 }; 62 63 } // namespace impl 64 65 /////////////////////////////////////////////////////////////////////////////// 66 // tag::weighted_sum 67 // 68 namespace tag 69 { 70 struct weighted_sum 71 : depends_on<> 72 { 73 /// INTERNAL ONLY 74 /// 75 typedef accumulators::impl::weighted_sum_impl<mpl::_1, mpl::_2, tag::sample> impl; 76 }; 77 78 template<typename VariateType, typename VariateTag> 79 struct weighted_sum_of_variates 80 : depends_on<> 81 { 82 /// INTERNAL ONLY 83 /// 84 typedef accumulators::impl::weighted_sum_impl<VariateType, mpl::_2, VariateTag> impl; 85 }; 86 87 struct abstract_weighted_sum_of_variates 88 : depends_on<> 89 { 90 }; 91 } 92 93 /////////////////////////////////////////////////////////////////////////////// 94 // extract::weighted_sum 95 // 96 namespace extract 97 { 98 extractor<tag::weighted_sum> const weighted_sum = {}; 99 extractor<tag::abstract_weighted_sum_of_variates> const weighted_sum_of_variates = {}; 100 101 BOOST_ACCUMULATORS_IGNORE_GLOBAL(weighted_sum) 102 BOOST_ACCUMULATORS_IGNORE_GLOBAL(weighted_sum_of_variates) 103 } 104 105 using extract::weighted_sum; 106 using extract::weighted_sum_of_variates; 107 108 template<typename VariateType, typename VariateTag> 109 struct feature_of<tag::weighted_sum_of_variates<VariateType, VariateTag> > 110 : feature_of<tag::abstract_weighted_sum_of_variates> 111 { 112 }; 113 114 }} // namespace boost::accumulators 115 116 #endif 117