boost/accumulators/statistics/sum.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // sum.hpp
   3 //
   4 //  Copyright 2005 Eric Niebler. 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_SUM_HPP_EAN_28_10_2005
   9 #define BOOST_ACCUMULATORS_STATISTICS_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 #include <boost/accumulators/statistics/count.hpp>
  21
  22 namespace boost { namespace accumulators
  23 {
  24
  25 namespace impl
  26 {
  27     ///////////////////////////////////////////////////////////////////////////////
  28     // sum_impl
  29     template<typename Sample, typename Tag>
  30     struct sum_impl
  31       : accumulator_base
  32     {
  33         // for boost::result_of
  34         typedef Sample result_type;
  35
  36         template<typename Args>
  37         sum_impl(Args const &args)
  38           : sum(args[parameter::keyword<Tag>::get() | Sample()])
  39         {
  40         }
  41
  42         template<typename Args>
  43         void operator ()(Args const &args)
  44         {
  45             // what about overflow?
  46             this->sum += args[parameter::keyword<Tag>::get()];
  47         }
  48
  49         result_type result(dont_care) const
  50         {
  51             return this->sum;
  52         }
  53
  54     private:
  55
  56         Sample sum;
  57     };
  58
  59 } // namespace impl
  60
  61 ///////////////////////////////////////////////////////////////////////////////
  62 // tag::sum
  63 // tag::sum_of_weights
  64 // tag::sum_of_variates
  65 //
  66 namespace tag
  67 {
  68     struct sum
  69       : depends_on<>
  70     {
  71         /// INTERNAL ONLY
  72         ///
  73         typedef accumulators::impl::sum_impl<mpl::_1, tag::sample> impl;
  74     };
  75
  76     struct sum_of_weights
  77       : depends_on<>
  78     {
  79         typedef mpl::true_ is_weight_accumulator;
  80         /// INTERNAL ONLY
  81         ///
  82         typedef accumulators::impl::sum_impl<mpl::_2, tag::weight> impl;
  83     };
  84
  85     template<typename VariateType, typename VariateTag>
  86     struct sum_of_variates
  87       : depends_on<>
  88     {
  89         /// INTERNAL ONLY
  90         ///
  91         typedef mpl::always<accumulators::impl::sum_impl<VariateType, VariateTag> > impl;
  92     };
  93
  94     struct abstract_sum_of_variates
  95       : depends_on<>
  96     {
  97     };
  98 }
  99
 100 ///////////////////////////////////////////////////////////////////////////////
 101 // extract::sum
 102 // extract::sum_of_weights
 103 // extract::sum_of_variates
 104 //
 105 namespace extract
 106 {
 107     extractor<tag::sum> const sum = {};
 108     extractor<tag::sum_of_weights> const sum_of_weights = {};
 109     extractor<tag::abstract_sum_of_variates> const sum_of_variates = {};
 110 }
 111
 112 using extract::sum;
 113 using extract::sum_of_weights;
 114 using extract::sum_of_variates;
 115
 116 // So that mean can be automatically substituted with
 117 // weighted_mean when the weight parameter is non-void.
 118 template<>
 119 struct as_weighted_feature<tag::sum>
 120 {
 121     typedef tag::weighted_sum type;
 122 };
 123
 124 template<>
 125 struct feature_of<tag::weighted_sum>
 126   : feature_of<tag::sum>
 127 {};
 128
 129 template<typename VariateType, typename VariateTag>
 130 struct feature_of<tag::sum_of_variates<VariateType, VariateTag> >
 131   : feature_of<tag::abstract_sum_of_variates>
 132 {
 133 };
 134
 135 }} // namespace boost::accumulators
 136
 137 #endif