boost/accumulators/statistics/error_of_mean.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // error_of.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_ERROR_OF_MEAN_HPP_EAN_27_03_2006
   9 #define BOOST_ACCUMULATORS_STATISTICS_ERROR_OF_MEAN_HPP_EAN_27_03_2006
  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/framework/depends_on.hpp>
  15 #include <boost/accumulators/statistics_fwd.hpp>
  16 #include <boost/accumulators/statistics/error_of.hpp>
  17 #include <boost/accumulators/statistics/variance.hpp>
  18 #include <boost/accumulators/statistics/count.hpp>
  19
  20 namespace boost { namespace accumulators
  21 {
  22
  23 namespace impl
  24 {
  25     ///////////////////////////////////////////////////////////////////////////////
  26     // error_of_mean_impl
  27     template<typename Sample, typename Variance>
  28     struct error_of_mean_impl
  29       : accumulator_base
  30     {
  31         // for boost::result_of
  32         typedef typename numeric::functional::average<Sample, std::size_t>::result_type result_type;
  33
  34         error_of_mean_impl(dont_care) {}
  35
  36         template<typename Args>
  37         result_type result(Args const &args) const
  38         {
  39             using namespace std;
  40             extractor<Variance> const variance = {};
  41             return sqrt(numeric::average(variance(args), count(args) - 1));
  42         }
  43     };
  44
  45 } // namespace impl
  46
  47 ///////////////////////////////////////////////////////////////////////////////
  48 // tag::error_of
  49 //
  50 namespace tag
  51 {
  52     template<>
  53     struct error_of<mean>
  54       : depends_on<lazy_variance, count>
  55     {
  56         /// INTERNAL ONLY
  57         ///
  58         typedef accumulators::impl::error_of_mean_impl<mpl::_1, lazy_variance> impl;
  59     };
  60
  61     template<>
  62     struct error_of<immediate_mean>
  63       : depends_on<variance, count>
  64     {
  65         /// INTERNAL ONLY
  66         ///
  67         typedef accumulators::impl::error_of_mean_impl<mpl::_1, variance> impl;
  68     };
  69 }
  70
  71 }} // namespace boost::accumulators
  72
  73 #endif