Chris@16: //  Copyright John Maddock 2007.
Chris@16: 
Chris@16: //  Use, modification and distribution are subject to the
Chris@16: //  Boost Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: /*
Chris@16: This header defines two traits classes, both in namespace boost::math::tools.
Chris@16: 
Chris@16: is_distribution<D>::value is true iff D has overloaded "cdf" and
Chris@16: "quantile" functions, plus member typedefs value_type and policy_type.  
Chris@16: It's not much of a definitive test frankly,
Chris@16: but if it looks like a distribution and quacks like a distribution
Chris@16: then it must be a distribution.
Chris@16: 
Chris@16: is_scaled_distribution<D>::value is true iff D is a distribution
Chris@16: as defined above, and has member functions "scale" and "location".
Chris@16: 
Chris@16: */
Chris@16: 
Chris@16: #ifndef BOOST_STATS_IS_DISTRIBUTION_HPP
Chris@16: #define BOOST_STATS_IS_DISTRIBUTION_HPP
Chris@16: 
Chris@16: #ifdef _MSC_VER
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/mpl/has_xxx.hpp>
Chris@16: // should be the last #include
Chris@16: #include <boost/type_traits/detail/bool_trait_def.hpp>
Chris@16: 
Chris@16: namespace boost{ namespace math{ namespace tools{
Chris@16: 
Chris@16: namespace detail{
Chris@16: 
Chris@16: BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_value_type, value_type, true)
Chris@16: BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_policy_type, policy_type, true)
Chris@16: 
Chris@16: template<class D>
Chris@16: char cdf(const D& ...);
Chris@16: template<class D>
Chris@16: char quantile(const D& ...);
Chris@16: 
Chris@16: template <class D>
Chris@16: struct has_cdf
Chris@16: {
Chris@16:    static D d;
Chris@16:    BOOST_STATIC_CONSTANT(bool, value = sizeof(cdf(d, 0.0f)) != 1);
Chris@16: };
Chris@16: 
Chris@16: template <class D>
Chris@16: struct has_quantile
Chris@16: {
Chris@16:    static D d;
Chris@16:    BOOST_STATIC_CONSTANT(bool, value = sizeof(quantile(d, 0.0f)) != 1);
Chris@16: };
Chris@16: 
Chris@16: template <class D>
Chris@16: struct is_distribution_imp
Chris@16: {
Chris@16:    BOOST_STATIC_CONSTANT(bool, value = 
Chris@16:       has_quantile<D>::value 
Chris@16:       && has_cdf<D>::value
Chris@16:       && has_value_type<D>::value
Chris@16:       && has_policy_type<D>::value);
Chris@16: };
Chris@16: 
Chris@16: template <class sig, sig val>
Chris@16: struct result_tag{};
Chris@16: 
Chris@16: template <class D>
Chris@16: double test_has_location(const volatile result_tag<typename D::value_type (D::*)()const, &D::location>*);
Chris@16: template <class D>
Chris@16: char test_has_location(...);
Chris@16: 
Chris@16: template <class D>
Chris@16: double test_has_scale(const volatile result_tag<typename D::value_type (D::*)()const, &D::scale>*);
Chris@16: template <class D>
Chris@16: char test_has_scale(...);
Chris@16: 
Chris@16: template <class D, bool b>
Chris@16: struct is_scaled_distribution_helper
Chris@16: {
Chris@16:    BOOST_STATIC_CONSTANT(bool, value = false);
Chris@16: };
Chris@16: 
Chris@16: template <class D>
Chris@16: struct is_scaled_distribution_helper<D, true>
Chris@16: {
Chris@16:    BOOST_STATIC_CONSTANT(bool, value = 
Chris@16:       (sizeof(test_has_location<D>(0)) != 1) 
Chris@16:       && 
Chris@16:       (sizeof(test_has_scale<D>(0)) != 1));
Chris@16: };
Chris@16: 
Chris@16: template <class D>
Chris@16: struct is_scaled_distribution_imp
Chris@16: {
Chris@16:    BOOST_STATIC_CONSTANT(bool, value = (::boost::math::tools::detail::is_scaled_distribution_helper<D, ::boost::math::tools::detail::is_distribution_imp<D>::value>::value));
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_distribution,T,::boost::math::tools::detail::is_distribution_imp<T>::value)
Chris@16: BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_scaled_distribution,T,::boost::math::tools::detail::is_scaled_distribution_imp<T>::value)
Chris@16: 
Chris@16: }}}
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: