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Diffstat (limited to 'src/third_party/boost-1.56.0/boost/random/triangle_distribution.hpp')
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diff --git a/src/third_party/boost-1.56.0/boost/random/triangle_distribution.hpp b/src/third_party/boost-1.56.0/boost/random/triangle_distribution.hpp new file mode 100644 index 00000000000..5ac6604713c --- /dev/null +++ b/src/third_party/boost-1.56.0/boost/random/triangle_distribution.hpp @@ -0,0 +1,232 @@ +/* boost random/triangle_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_TRIANGLE_DISTRIBUTION_HPP +#define BOOST_RANDOM_TRIANGLE_DISTRIBUTION_HPP + +#include <boost/config/no_tr1/cmath.hpp> +#include <iosfwd> +#include <ios> +#include <istream> +#include <boost/assert.hpp> +#include <boost/random/detail/config.hpp> +#include <boost/random/detail/operators.hpp> +#include <boost/random/uniform_01.hpp> + +namespace boost { +namespace random { + +/** + * Instantiations of @c triangle_distribution model a \random_distribution. + * A @c triangle_distribution has three parameters, @c a, @c b, and @c c, + * which are the smallest, the most probable and the largest values of + * the distribution respectively. + */ +template<class RealType = double> +class triangle_distribution +{ +public: + typedef RealType input_type; + typedef RealType result_type; + + class param_type + { + public: + + typedef triangle_distribution distribution_type; + + /** Constructs the parameters of a @c triangle_distribution. */ + explicit param_type(RealType a_arg = RealType(0.0), + RealType b_arg = RealType(0.5), + RealType c_arg = RealType(1.0)) + : _a(a_arg), _b(b_arg), _c(c_arg) + { + BOOST_ASSERT(_a <= _b && _b <= _c); + } + + /** Returns the minimum value of the distribution. */ + RealType a() const { return _a; } + /** Returns the mode of the distribution. */ + RealType b() const { return _b; } + /** Returns the maximum value of the distribution. */ + RealType c() const { return _c; } + + /** Writes the parameters to a @c std::ostream. */ + BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, param_type, parm) + { + os << parm._a << " " << parm._b << " " << parm._c; + return os; + } + + /** Reads the parameters from a @c std::istream. */ + BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, param_type, parm) + { + double a_in, b_in, c_in; + if(is >> a_in >> std::ws >> b_in >> std::ws >> c_in) { + if(a_in <= b_in && b_in <= c_in) { + parm._a = a_in; + parm._b = b_in; + parm._c = c_in; + } else { + is.setstate(std::ios_base::failbit); + } + } + return is; + } + + /** Returns true if the two sets of parameters are equal. */ + BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(param_type, lhs, rhs) + { return lhs._a == rhs._a && lhs._b == rhs._b && lhs._c == rhs._c; } + + /** Returns true if the two sets of parameters are different. */ + BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(param_type) + + private: + RealType _a; + RealType _b; + RealType _c; + }; + + /** + * Constructs a @c triangle_distribution with the parameters + * @c a, @c b, and @c c. + * + * Preconditions: a <= b <= c. + */ + explicit triangle_distribution(RealType a_arg = RealType(0.0), + RealType b_arg = RealType(0.5), + RealType c_arg = RealType(1.0)) + : _a(a_arg), _b(b_arg), _c(c_arg) + { + BOOST_ASSERT(_a <= _b && _b <= _c); + init(); + } + + /** Constructs a @c triangle_distribution from its parameters. */ + explicit triangle_distribution(const param_type& parm) + : _a(parm.a()), _b(parm.b()), _c(parm.c()) + { + init(); + } + + // compiler-generated copy ctor and assignment operator are fine + + /** Returns the @c a parameter of the distribution */ + result_type a() const { return _a; } + /** Returns the @c b parameter of the distribution */ + result_type b() const { return _b; } + /** Returns the @c c parameter of the distribution */ + result_type c() const { return _c; } + + /** Returns the smallest value that the distribution can produce. */ + RealType min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return _a; } + /** Returns the largest value that the distribution can produce. */ + RealType max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return _c; } + + /** Returns the parameters of the distribution. */ + param_type param() const { return param_type(_a, _b, _c); } + /** Sets the parameters of the distribution. */ + void param(const param_type& parm) + { + _a = parm.a(); + _b = parm.b(); + _c = parm.c(); + init(); + } + + /** + * 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 + * triangle distribution. + */ + template<class Engine> + result_type operator()(Engine& eng) + { + using std::sqrt; + result_type u = uniform_01<>()(eng); + if( u <= q1 ) + return _a + p1*sqrt(u); + else + return _c - d3*sqrt(d2*u-d1); + } + + /** + * Returns a random variate distributed according to the + * triangle distribution with parameters specified by param. + */ + template<class Engine> + result_type operator()(Engine& eng, const param_type& parm) + { return triangle_distribution(parm)(eng); } + + /** Writes the distribution to a @c std::ostream. */ + BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, triangle_distribution, td) + { + os << td.param(); + return os; + } + + /** Reads the distribution from a @c std::istream. */ + BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, triangle_distribution, td) + { + param_type parm; + if(is >> parm) { + td.param(parm); + } + return is; + } + + /** + * Returns true if the two distributions will produce identical + * sequences of values given equal generators. + */ + BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(triangle_distribution, lhs, rhs) + { return lhs._a == rhs._a && lhs._b == rhs._b && lhs._c == rhs._c; } + + /** + * Returns true if the two distributions may produce different + * sequences of values given equal generators. + */ + BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(triangle_distribution) + +private: + /// \cond show_private + void init() + { + using std::sqrt; + d1 = _b - _a; + d2 = _c - _a; + d3 = sqrt(_c - _b); + q1 = d1 / d2; + p1 = sqrt(d1 * d2); + } + /// \endcond + + RealType _a, _b, _c; + RealType d1, d2, d3, q1, p1; +}; + +} // namespace random + +using random::triangle_distribution; + +} // namespace boost + +#endif // BOOST_RANDOM_TRIANGLE_DISTRIBUTION_HPP |