| /* boost random/bernoulli_distribution.hpp header file |
| * |
| * Copyright Jens Maurer 2000-2001 |
| * 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) |
| * |
| * See http://www.boost.org for most recent version including documentation. |
| * |
| * $Id: bernoulli_distribution.hpp 52492 2009-04-19 14:55:57Z steven_watanabe $ |
| * |
| * Revision history |
| * 2001-02-18 moved to individual header files |
| */ |
| |
| #ifndef BOOST_RANDOM_BERNOULLI_DISTRIBUTION_HPP |
| #define BOOST_RANDOM_BERNOULLI_DISTRIBUTION_HPP |
| |
| #include <cassert> |
| #include <iostream> |
| #include <boost/random/detail/config.hpp> |
| |
| namespace boost { |
| |
| // Bernoulli distribution: p(true) = p, p(false) = 1-p (boolean) |
| template<class RealType = double> |
| class bernoulli_distribution |
| { |
| public: |
| // In principle, this could work with both integer and floating-point |
| // types. Generating floating-point random numbers in the first |
| // place is probably more expensive, so use integer as input. |
| typedef int input_type; |
| typedef bool result_type; |
| |
| explicit bernoulli_distribution(const RealType& p_arg = RealType(0.5)) |
| : _p(p_arg) |
| { |
| assert(_p >= 0); |
| assert(_p <= 1); |
| } |
| |
| // compiler-generated copy ctor and assignment operator are fine |
| |
| RealType p() const { return _p; } |
| void reset() { } |
| |
| template<class Engine> |
| result_type operator()(Engine& eng) |
| { |
| if(_p == RealType(0)) |
| return false; |
| else |
| return RealType(eng() - (eng.min)()) <= _p * RealType((eng.max)()-(eng.min)()); |
| } |
| |
| #ifndef BOOST_RANDOM_NO_STREAM_OPERATORS |
| template<class CharT, class Traits> |
| friend std::basic_ostream<CharT,Traits>& |
| operator<<(std::basic_ostream<CharT,Traits>& os, const bernoulli_distribution& bd) |
| { |
| os << bd._p; |
| return os; |
| } |
| |
| template<class CharT, class Traits> |
| friend std::basic_istream<CharT,Traits>& |
| operator>>(std::basic_istream<CharT,Traits>& is, bernoulli_distribution& bd) |
| { |
| is >> std::ws >> bd._p; |
| return is; |
| } |
| #endif |
| |
| private: |
| RealType _p; |
| }; |
| |
| } // namespace boost |
| |
| #endif // BOOST_RANDOM_BERNOULLI_DISTRIBUTION_HPP |