]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | // Copyright John Maddock 2007. |
2 | ||
3 | // Use, modification and distribution are subject to the | |
4 | // Boost Software License, Version 1.0. (See accompanying file | |
5 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | ||
7 | /* | |
8 | This header defines two traits classes, both in namespace boost::math::tools. | |
9 | ||
10 | is_distribution<D>::value is true iff D has overloaded "cdf" and | |
11 | "quantile" functions, plus member typedefs value_type and policy_type. | |
12 | It's not much of a definitive test frankly, | |
13 | but if it looks like a distribution and quacks like a distribution | |
14 | then it must be a distribution. | |
15 | ||
16 | is_scaled_distribution<D>::value is true iff D is a distribution | |
17 | as defined above, and has member functions "scale" and "location". | |
18 | ||
19 | */ | |
20 | ||
21 | #ifndef BOOST_STATS_IS_DISTRIBUTION_HPP | |
22 | #define BOOST_STATS_IS_DISTRIBUTION_HPP | |
23 | ||
24 | #ifdef _MSC_VER | |
25 | #pragma once | |
26 | #endif | |
27 | ||
28 | #include <boost/mpl/has_xxx.hpp> | |
29 | #include <boost/type_traits/integral_constant.hpp> | |
30 | ||
31 | namespace boost{ namespace math{ namespace tools{ | |
32 | ||
33 | namespace detail{ | |
34 | ||
35 | BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_value_type, value_type, true) | |
36 | BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_policy_type, policy_type, true) | |
37 | ||
38 | template<class D> | |
39 | char cdf(const D& ...); | |
40 | template<class D> | |
41 | char quantile(const D& ...); | |
42 | ||
43 | template <class D> | |
44 | struct has_cdf | |
45 | { | |
46 | static D d; | |
47 | BOOST_STATIC_CONSTANT(bool, value = sizeof(cdf(d, 0.0f)) != 1); | |
48 | }; | |
49 | ||
50 | template <class D> | |
51 | struct has_quantile | |
52 | { | |
53 | static D d; | |
54 | BOOST_STATIC_CONSTANT(bool, value = sizeof(quantile(d, 0.0f)) != 1); | |
55 | }; | |
56 | ||
57 | template <class D> | |
58 | struct is_distribution_imp | |
59 | { | |
60 | BOOST_STATIC_CONSTANT(bool, value = | |
61 | has_quantile<D>::value | |
62 | && has_cdf<D>::value | |
63 | && has_value_type<D>::value | |
64 | && has_policy_type<D>::value); | |
65 | }; | |
66 | ||
67 | template <class sig, sig val> | |
68 | struct result_tag{}; | |
69 | ||
70 | template <class D> | |
71 | double test_has_location(const volatile result_tag<typename D::value_type (D::*)()const, &D::location>*); | |
72 | template <class D> | |
73 | char test_has_location(...); | |
74 | ||
75 | template <class D> | |
76 | double test_has_scale(const volatile result_tag<typename D::value_type (D::*)()const, &D::scale>*); | |
77 | template <class D> | |
78 | char test_has_scale(...); | |
79 | ||
80 | template <class D, bool b> | |
81 | struct is_scaled_distribution_helper | |
82 | { | |
83 | BOOST_STATIC_CONSTANT(bool, value = false); | |
84 | }; | |
85 | ||
86 | template <class D> | |
87 | struct is_scaled_distribution_helper<D, true> | |
88 | { | |
89 | BOOST_STATIC_CONSTANT(bool, value = | |
90 | (sizeof(test_has_location<D>(0)) != 1) | |
91 | && | |
92 | (sizeof(test_has_scale<D>(0)) != 1)); | |
93 | }; | |
94 | ||
95 | template <class D> | |
96 | struct is_scaled_distribution_imp | |
97 | { | |
98 | BOOST_STATIC_CONSTANT(bool, value = (::boost::math::tools::detail::is_scaled_distribution_helper<D, ::boost::math::tools::detail::is_distribution_imp<D>::value>::value)); | |
99 | }; | |
100 | ||
101 | } // namespace detail | |
102 | ||
103 | template <class T> struct is_distribution : public boost::integral_constant<bool, ::boost::math::tools::detail::is_distribution_imp<T>::value> {}; | |
104 | template <class T> struct is_scaled_distribution : public boost::integral_constant<bool, ::boost::math::tools::detail::is_scaled_distribution_imp<T>::value> {}; | |
105 | ||
106 | }}} | |
107 | ||
108 | #endif | |
109 | ||
110 |