| /////////////////////////////////////////////////////////////////////////////// |
| // 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 |