98 lines
3.0 KiB
C++
Executable File
98 lines
3.0 KiB
C++
Executable File
/* boost random/uniform_01.hpp header file
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*
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* Copyright Jens Maurer 2000-2001
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* Distributed under the Boost Software License, Version 1.0. (See
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* accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* See http://www.boost.org for most recent version including documentation.
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*
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* $Id: uniform_01.hpp 41369 2007-11-25 18:07:19Z bemandawes $
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*
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* Revision history
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* 2001-02-18 moved to individual header files
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*/
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#ifndef BOOST_RANDOM_UNIFORM_01_HPP
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#define BOOST_RANDOM_UNIFORM_01_HPP
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#include <iostream>
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#include <boost/config.hpp>
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#include <boost/limits.hpp>
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#include <boost/static_assert.hpp>
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namespace boost {
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// Because it is so commonly used: uniform distribution on the real [0..1)
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// range. This allows for specializations to avoid a costly int -> float
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// conversion plus float multiplication
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template<class UniformRandomNumberGenerator, class RealType = double>
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class uniform_01
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{
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public:
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typedef UniformRandomNumberGenerator base_type;
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typedef RealType result_type;
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BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
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#if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) && !(defined(BOOST_MSVC) && BOOST_MSVC <= 1300)
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BOOST_STATIC_ASSERT(!std::numeric_limits<RealType>::is_integer);
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#endif
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explicit uniform_01(base_type rng)
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: _rng(rng),
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_factor(result_type(1) /
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(result_type((_rng.max)()-(_rng.min)()) +
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result_type(std::numeric_limits<base_result>::is_integer ? 1 : 0)))
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{
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}
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// compiler-generated copy ctor and copy assignment are fine
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result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(0); }
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result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(1); }
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base_type& base() { return _rng; }
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const base_type& base() const { return _rng; }
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void reset() { }
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result_type operator()() {
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for (;;) {
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result_type result = result_type(_rng() - (_rng.min)()) * _factor;
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if (result < result_type(1))
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return result;
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}
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}
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#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
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template<class CharT, class Traits>
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friend std::basic_ostream<CharT,Traits>&
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operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_01& u)
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{
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os << u._rng;
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return os;
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}
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template<class CharT, class Traits>
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friend std::basic_istream<CharT,Traits>&
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operator>>(std::basic_istream<CharT,Traits>& is, uniform_01& u)
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{
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is >> u._rng;
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return is;
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}
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#endif
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private:
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typedef typename base_type::result_type base_result;
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base_type _rng;
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result_type _factor;
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};
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#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
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// A definition is required even for integral static constants
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template<class UniformRandomNumberGenerator, class RealType>
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const bool uniform_01<UniformRandomNumberGenerator, RealType>::has_fixed_range;
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#endif
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} // namespace boost
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#endif // BOOST_RANDOM_UNIFORM_01_HPP
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