/////////////////////////////////////////////////////////////////////////////// | |
// weighted_moment.hpp | |
// | |
// Copyright 2006, Eric Niebler, Olivier Gygi. 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_WEIGHTED_MOMENT_HPP_EAN_15_11_2005 | |
#define BOOST_ACCUMULATORS_STATISTICS_WEIGHTED_MOMENT_HPP_EAN_15_11_2005 | |
#include <boost/config/no_tr1/cmath.hpp> | |
#include <boost/mpl/int.hpp> | |
#include <boost/mpl/assert.hpp> | |
#include <boost/mpl/placeholders.hpp> | |
#include <boost/preprocessor/arithmetic/inc.hpp> | |
#include <boost/preprocessor/repetition/repeat_from_to.hpp> | |
#include <boost/preprocessor/repetition/enum_trailing_params.hpp> | |
#include <boost/preprocessor/repetition/enum_trailing_binary_params.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/moment.hpp> // for pow() | |
#include <boost/accumulators/statistics/sum.hpp> | |
namespace boost { namespace accumulators | |
{ | |
namespace impl | |
{ | |
/////////////////////////////////////////////////////////////////////////////// | |
// weighted_moment_impl | |
template<typename N, typename Sample, typename Weight> | |
struct weighted_moment_impl | |
: accumulator_base // TODO: also depends_on sum of powers | |
{ | |
BOOST_MPL_ASSERT_RELATION(N::value, >, 0); | |
typedef typename numeric::functional::multiplies<Sample, Weight>::result_type weighted_sample; | |
// for boost::result_of | |
typedef typename numeric::functional::average<weighted_sample, Weight>::result_type result_type; | |
template<typename Args> | |
weighted_moment_impl(Args const &args) | |
: sum(args[sample | Sample()] * numeric::one<Weight>::value) | |
{ | |
} | |
template<typename Args> | |
void operator ()(Args const &args) | |
{ | |
this->sum += args[weight] * numeric::pow(args[sample], N()); | |
} | |
template<typename Args> | |
result_type result(Args const &args) const | |
{ | |
return numeric::average(this->sum, sum_of_weights(args)); | |
} | |
private: | |
weighted_sample sum; | |
}; | |
} // namespace impl | |
/////////////////////////////////////////////////////////////////////////////// | |
// tag::weighted_moment | |
// | |
namespace tag | |
{ | |
template<int N> | |
struct weighted_moment | |
: depends_on<count, sum_of_weights> | |
{ | |
/// INTERNAL ONLY | |
/// | |
typedef accumulators::impl::weighted_moment_impl<mpl::int_<N>, mpl::_1, mpl::_2> impl; | |
}; | |
} | |
/////////////////////////////////////////////////////////////////////////////// | |
// extract::weighted_moment | |
// | |
namespace extract | |
{ | |
BOOST_ACCUMULATORS_DEFINE_EXTRACTOR(tag, weighted_moment, (int)) | |
} | |
using extract::weighted_moment; | |
}} // namespace boost::accumulators | |
#endif |