diff options
Diffstat (limited to 'src/third_party/boost-1.60.0/boost/random/bernoulli_distribution.hpp')
-rw-r--r-- | src/third_party/boost-1.60.0/boost/random/bernoulli_distribution.hpp | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/src/third_party/boost-1.60.0/boost/random/bernoulli_distribution.hpp b/src/third_party/boost-1.60.0/boost/random/bernoulli_distribution.hpp new file mode 100644 index 00000000000..d66bae4389d --- /dev/null +++ b/src/third_party/boost-1.60.0/boost/random/bernoulli_distribution.hpp @@ -0,0 +1,197 @@ +/* boost random/bernoulli_distribution.hpp header file + * + * Copyright Jens Maurer 2000-2001 + * Copyright Steven Watanabe 2011 + * 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. + * + * $Id$ + * + * Revision history + * 2001-02-18 moved to individual header files + */ + +#ifndef BOOST_RANDOM_BERNOULLI_DISTRIBUTION_HPP +#define BOOST_RANDOM_BERNOULLI_DISTRIBUTION_HPP + +#include <iosfwd> +#include <boost/assert.hpp> +#include <boost/random/detail/config.hpp> +#include <boost/random/detail/operators.hpp> + +namespace boost { +namespace random { + +/** + * Instantiations of class template \bernoulli_distribution model a + * \random_distribution. Such a random distribution produces bool values + * distributed with probabilities P(true) = p and P(false) = 1-p. p is + * the parameter of the distribution. + */ +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; + + class param_type + { + public: + + typedef bernoulli_distribution distribution_type; + + /** + * Constructs the parameters of the distribution. + * + * Requires: 0 <= p <= 1 + */ + explicit param_type(RealType p_arg = RealType(0.5)) + : _p(p_arg) + { + BOOST_ASSERT(_p >= 0); + BOOST_ASSERT(_p <= 1); + } + + /** Returns the p parameter of the distribution. */ + RealType p() const { return _p; } + + /** Writes the parameters to a std::ostream. */ + BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, param_type, parm) + { + os << parm._p; + return os; + } + + /** Reads the parameters from a std::istream. */ + BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, param_type, parm) + { + is >> parm._p; + return is; + } + + /** Returns true if the two sets of parameters are equal. */ + BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(param_type, lhs, rhs) + { return lhs._p == rhs._p; } + + /** Returns true if the two sets of parameters are different. */ + BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(param_type) + + private: + RealType _p; + }; + + /** + * Constructs a \bernoulli_distribution object. + * p is the parameter of the distribution. + * + * Requires: 0 <= p <= 1 + */ + explicit bernoulli_distribution(const RealType& p_arg = RealType(0.5)) + : _p(p_arg) + { + BOOST_ASSERT(_p >= 0); + BOOST_ASSERT(_p <= 1); + } + /** + * Constructs \bernoulli_distribution from its parameters + */ + explicit bernoulli_distribution(const param_type& parm) + : _p(parm.p()) {} + + // compiler-generated copy ctor and assignment operator are fine + + /** + * Returns: The "p" parameter of the distribution. + */ + RealType p() const { return _p; } + + /** Returns the smallest value that the distribution can produce. */ + bool min BOOST_PREVENT_MACRO_SUBSTITUTION () const + { return false; } + /** Returns the largest value that the distribution can produce. */ + bool max BOOST_PREVENT_MACRO_SUBSTITUTION () const + { return true; } + + /** Returns the parameters of the distribution. */ + param_type param() const { return param_type(_p); } + /** Sets the parameters of the distribution. */ + void param(const param_type& parm) { _p = parm.p(); } + + /** + * Effects: Subsequent uses of the distribution do not depend + * on values produced by any engine prior to invoking reset. + */ + void reset() { } + + /** + * Returns: a random variate distributed according to the + * \bernoulli_distribution. + */ + template<class Engine> + bool operator()(Engine& eng) const + { + if(_p == RealType(0)) + return false; + else + return RealType(eng() - (eng.min)()) <= _p * RealType((eng.max)()-(eng.min)()); + } + + /** + * Returns: a random variate distributed according to the + * \bernoulli_distribution with parameters specified by param. + */ + template<class Engine> + bool operator()(Engine& eng, const param_type& parm) const + { + return bernoulli_distribution(parm)(eng); + } + + /** + * Writes the parameters of the distribution to a @c std::ostream. + */ + BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, bernoulli_distribution, bd) + { + os << bd._p; + return os; + } + + /** + * Reads the parameters of the distribution from a @c std::istream. + */ + BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, bernoulli_distribution, bd) + { + is >> bd._p; + return is; + } + + /** + * Returns true iff the two distributions will produce identical + * sequences of values given equal generators. + */ + BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(bernoulli_distribution, lhs, rhs) + { return lhs._p == rhs._p; } + + /** + * Returns true iff the two distributions will produce different + * sequences of values given equal generators. + */ + BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(bernoulli_distribution) + +private: + RealType _p; +}; + +} // namespace random + +using random::bernoulli_distribution; + +} // namespace boost + +#endif // BOOST_RANDOM_BERNOULLI_DISTRIBUTION_HPP |