ceph/src/boost/libs/accumulators/include/boost/accumulators/statistics/weighted_sum.hpp

   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>
  38         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>
  47         void operator ()(Args const &args)
  48         {
  49             // what about overflow?
  50             this->weighted_sum_ += args[parameter::keyword<Tag>::get()] * args[weight];
  51         }
  52
  53         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