[857] | 1 | /* boost random/uniform_01.hpp header file
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| 2 | *
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| 3 | * Copyright Jens Maurer 2000-2001
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| 4 | * Distributed under the Boost Software License, Version 1.0. (See
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| 5 | * accompanying file LICENSE_1_0.txt or copy at
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| 6 | * http://www.boost.org/LICENSE_1_0.txt)
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| 7 | *
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| 8 | * See http://www.boost.org for most recent version including documentation.
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| 9 | *
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| 10 | * $Id: uniform_01.hpp,v 1.18 2004/07/27 03:43:32 dgregor Exp $
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| 11 | *
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| 12 | * Revision history
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| 13 | * 2001-02-18 moved to individual header files
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| 14 | */
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| 15 |
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| 16 | #ifndef BOOST_RANDOM_UNIFORM_01_HPP
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| 17 | #define BOOST_RANDOM_UNIFORM_01_HPP
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| 18 |
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| 19 | #include <iostream>
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| 20 | #include <boost/config.hpp>
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| 21 | #include <boost/limits.hpp>
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| 22 | #include <boost/static_assert.hpp>
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| 23 |
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| 24 | namespace boost {
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| 25 |
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| 26 | // Because it is so commonly used: uniform distribution on the real [0..1)
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| 27 | // range. This allows for specializations to avoid a costly int -> float
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| 28 | // conversion plus float multiplication
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| 29 | template<class UniformRandomNumberGenerator, class RealType = double>
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| 30 | class uniform_01
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| 31 | {
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| 32 | public:
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| 33 | typedef UniformRandomNumberGenerator base_type;
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| 34 | typedef RealType result_type;
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| 35 |
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| 36 | BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
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| 37 |
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| 38 | #if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) && !(defined(BOOST_MSVC) && BOOST_MSVC <= 1300)
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| 39 | BOOST_STATIC_ASSERT(!std::numeric_limits<RealType>::is_integer);
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| 40 | #endif
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| 41 |
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| 42 | explicit uniform_01(base_type rng)
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| 43 | : _rng(rng),
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| 44 | _factor(result_type(1) /
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| 45 | (result_type((_rng.max)()-(_rng.min)()) +
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| 46 | result_type(std::numeric_limits<base_result>::is_integer ? 1 : 0)))
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| 47 | {
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| 48 | }
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| 49 | // compiler-generated copy ctor and copy assignment are fine
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| 50 |
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| 51 | result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(0); }
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| 52 | result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(1); }
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| 53 | base_type& base() { return _rng; }
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| 54 | const base_type& base() const { return _rng; }
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| 55 | void reset() { }
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| 56 |
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| 57 | result_type operator()() {
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| 58 | return result_type(_rng() - (_rng.min)()) * _factor;
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| 59 | }
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| 60 |
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| 61 | #if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
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| 62 | template<class CharT, class Traits>
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| 63 | friend std::basic_ostream<CharT,Traits>&
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| 64 | operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_01& u)
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| 65 | {
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| 66 | os << u._rng;
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| 67 | return os;
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| 68 | }
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| 69 |
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| 70 | template<class CharT, class Traits>
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| 71 | friend std::basic_istream<CharT,Traits>&
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| 72 | operator>>(std::basic_istream<CharT,Traits>& is, uniform_01& u)
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| 73 | {
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| 74 | is >> u._rng;
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| 75 | return is;
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| 76 | }
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| 77 | #endif
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| 78 |
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| 79 | private:
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| 80 | typedef typename base_type::result_type base_result;
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| 81 | base_type _rng;
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| 82 | result_type _factor;
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| 83 | };
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| 84 |
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| 85 | #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
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| 86 | // A definition is required even for integral static constants
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| 87 | template<class UniformRandomNumberGenerator, class RealType>
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| 88 | const bool uniform_01<UniformRandomNumberGenerator, RealType>::has_fixed_range;
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| 89 | #endif
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| 90 |
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| 91 | } // namespace boost
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| 92 |
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| 93 | #endif // BOOST_RANDOM_UNIFORM_01_HPP
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