1 | /////////////////////////////////////////////////////////////////////////////// |
2 | // weighted_moment.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_MOMENT_HPP_EAN_15_11_2005 |
9 | #define BOOST_ACCUMULATORS_STATISTICS_WEIGHTED_MOMENT_HPP_EAN_15_11_2005 |
10 | |
11 | #include <boost/config/no_tr1/cmath.hpp> |
12 | #include <boost/mpl/int.hpp> |
13 | #include <boost/mpl/assert.hpp> |
14 | #include <boost/mpl/placeholders.hpp> |
15 | #include <boost/preprocessor/arithmetic/inc.hpp> |
16 | #include <boost/preprocessor/repetition/repeat_from_to.hpp> |
17 | #include <boost/preprocessor/repetition/enum_trailing_params.hpp> |
18 | #include <boost/preprocessor/repetition/enum_trailing_binary_params.hpp> |
19 | #include <boost/accumulators/framework/accumulator_base.hpp> |
20 | #include <boost/accumulators/framework/extractor.hpp> |
21 | #include <boost/accumulators/numeric/functional.hpp> |
22 | #include <boost/accumulators/framework/parameters/sample.hpp> |
23 | #include <boost/accumulators/framework/depends_on.hpp> |
24 | #include <boost/accumulators/statistics_fwd.hpp> |
25 | #include <boost/accumulators/statistics/count.hpp> |
26 | #include <boost/accumulators/statistics/moment.hpp> // for pow() |
27 | #include <boost/accumulators/statistics/sum.hpp> |
28 | |
29 | namespace boost { namespace accumulators |
30 | { |
31 | |
32 | namespace impl |
33 | { |
34 | /////////////////////////////////////////////////////////////////////////////// |
35 | // weighted_moment_impl |
36 | template<typename N, typename Sample, typename Weight> |
37 | struct weighted_moment_impl |
38 | : accumulator_base // TODO: also depends_on sum of powers |
39 | { |
40 | BOOST_MPL_ASSERT_RELATION(N::value, >, 0); |
41 | typedef typename numeric::functional::multiplies<Sample, Weight>::result_type weighted_sample; |
42 | // for boost::result_of |
43 | typedef typename numeric::functional::fdiv<weighted_sample, Weight>::result_type result_type; |
44 | |
45 | template<typename Args> |
46 | weighted_moment_impl(Args const &args) |
47 | : sum(args[sample | Sample()] * numeric::one<Weight>::value) |
48 | { |
49 | } |
50 | |
51 | template<typename Args> |
52 | void operator ()(Args const &args) |
53 | { |
54 | this->sum += args[weight] * numeric::pow(args[sample], N()); |
55 | } |
56 | |
57 | template<typename Args> |
58 | result_type result(Args const &args) const |
59 | { |
60 | return numeric::fdiv(this->sum, sum_of_weights(args)); |
61 | } |
62 | |
63 | // make this accumulator serializeable |
64 | template<class Archive> |
65 | void serialize(Archive & ar, const unsigned int file_version) |
66 | { |
67 | ar & sum; |
68 | } |
69 | |
70 | private: |
71 | weighted_sample sum; |
72 | }; |
73 | |
74 | } // namespace impl |
75 | |
76 | /////////////////////////////////////////////////////////////////////////////// |
77 | // tag::weighted_moment |
78 | // |
79 | namespace tag |
80 | { |
81 | template<int N> |
82 | struct weighted_moment |
83 | : depends_on<count, sum_of_weights> |
84 | { |
85 | /// INTERNAL ONLY |
86 | /// |
87 | typedef accumulators::impl::weighted_moment_impl<mpl::int_<N>, mpl::_1, mpl::_2> impl; |
88 | }; |
89 | } |
90 | |
91 | /////////////////////////////////////////////////////////////////////////////// |
92 | // extract::weighted_moment |
93 | // |
94 | namespace extract |
95 | { |
96 | BOOST_ACCUMULATORS_DEFINE_EXTRACTOR(tag, , (int)) |
97 | } |
98 | |
99 | using extract::weighted_moment; |
100 | |
101 | }} // namespace boost::accumulators |
102 | |
103 | #endif |
104 | |