1 /* boost random/variate_generator.hpp header file 2 * 3 * Copyright Jens Maurer 2002 4 * Copyright Steven Watanabe 2011 5 * Distributed under the Boost Software License, Version 1.0. (See 6 * accompanying file LICENSE_1_0.txt or copy at 7 * http://www.boost.org/LICENSE_1_0.txt) 8 * 9 * See http://www.boost.org for most recent version including documentation. 10 * 11 * $Id$ 12 * 13 */ 14 15 #ifndef BOOST_RANDOM_RANDOM_GENERATOR_HPP 16 #define BOOST_RANDOM_RANDOM_GENERATOR_HPP 17 18 #include <boost/random/detail/ptr_helper.hpp> 19 20 #include <boost/random/detail/disable_warnings.hpp> 21 22 namespace boost { 23 24 /// \cond hide_private_members 25 26 namespace random { 27 28 ///\endcond 29 30 /** 31 * A random variate generator is used to join a random number 32 * generator together with a random number distribution. 33 * Boost.Random provides a vast choice of \generators as well 34 * as \distributions. 35 * 36 * The argument for the template parameter Engine shall be of 37 * the form U, U&, or U*, where U models a 38 * \uniform_random_number_generator. Then, the member 39 * engine_value_type names U (not the pointer or reference to U). 40 * 41 * Specializations of @c variate_generator satisfy the 42 * requirements of CopyConstructible. They also satisfy the 43 * requirements of Assignable unless the template parameter 44 * Engine is of the form U&. 45 * 46 * The complexity of all functions specified in this section 47 * is constant. No function described in this section except 48 * the constructor throws an exception. 49 */ 50 template<class Engine, class Distribution> 51 class variate_generator 52 { 53 private: 54 typedef boost::random::detail::ptr_helper<Engine> helper_type; 55 public: 56 typedef typename helper_type::value_type engine_value_type; 57 typedef Engine engine_type; 58 typedef Distribution distribution_type; 59 typedef typename Distribution::result_type result_type; 60 61 /** 62 * Constructs a @c variate_generator object with the associated 63 * \uniform_random_number_generator eng and the associated 64 * \random_distribution d. 65 * 66 * Throws: If and what the copy constructor of Engine or 67 * Distribution throws. 68 */ variate_generator(Engine e,Distribution d)69 variate_generator(Engine e, Distribution d) 70 : _eng(e), _dist(d) { } 71 72 /** Returns: distribution()(engine()) */ operator ()()73 result_type operator()() { return _dist(engine()); } 74 /** 75 * Returns: distribution()(engine(), value). 76 */ 77 template<class T> operator ()(const T & value)78 result_type operator()(const T& value) { return _dist(engine(), value); } 79 80 /** 81 * Returns: A reference to the associated uniform random number generator. 82 */ engine()83 engine_value_type& engine() { return helper_type::ref(_eng); } 84 /** 85 * Returns: A reference to the associated uniform random number generator. 86 */ engine() const87 const engine_value_type& engine() const { return helper_type::ref(_eng); } 88 89 /** Returns: A reference to the associated \random_distribution. */ distribution()90 distribution_type& distribution() { return _dist; } 91 /** 92 * Returns: A reference to the associated random distribution. 93 */ distribution() const94 const distribution_type& distribution() const { return _dist; } 95 96 /** 97 * Precondition: distribution().min() is well-formed 98 * 99 * Returns: distribution().min() 100 */ BOOST_PREVENT_MACRO_SUBSTITUTION() const101 result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (distribution().min)(); } 102 /** 103 * Precondition: distribution().max() is well-formed 104 * 105 * Returns: distribution().max() 106 */ BOOST_PREVENT_MACRO_SUBSTITUTION() const107 result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (distribution().max)(); } 108 109 private: 110 Engine _eng; 111 distribution_type _dist; 112 }; 113 114 } // namespace random 115 116 using random::variate_generator; 117 118 } // namespace boost 119 120 #include <boost/random/detail/enable_warnings.hpp> 121 122 #endif // BOOST_RANDOM_RANDOM_GENERATOR_HPP 123