1 /* boost random/uniform_01.hpp header file

     2  *

     3  * Copyright Jens Maurer 2000-2001

     4  * Distributed under the Boost Software License, Version 1.0. (See

     5  * accompanying file LICENSE_1_0.txt or copy at

     6  * http://www.boost.org/LICENSE_1_0.txt)

     7  *

     8  * See http://www.boost.org for most recent version including documentation.

     9  *

    10  * $Id: uniform_01.hpp,v 1.18 2004/07/27 03:43:32 dgregor Exp $

    11  *

    12  * Revision history

    13  *  2001-02-18  moved to individual header files

    14  */

    15 

    16 #ifndef BOOST_RANDOM_UNIFORM_01_HPP

    17 #define BOOST_RANDOM_UNIFORM_01_HPP

    18 

    19 #include <iostream>

    20 #include <boost/config.hpp>

    21 #include <boost/limits.hpp>

    22 #include <boost/static_assert.hpp>

    23 

    24 namespace boost {

    25 

    26 // Because it is so commonly used: uniform distribution on the real [0..1)

    27 // range.  This allows for specializations to avoid a costly int -> float

    28 // conversion plus float multiplication

    29 template<class UniformRandomNumberGenerator, class RealType = double>

    30 class uniform_01

    31 {

    32 public:

    33   typedef UniformRandomNumberGenerator base_type;

    34   typedef RealType result_type;

    35 

    36   BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);

    37 

    38 #if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) && !(defined(BOOST_MSVC) && BOOST_MSVC <= 1300)

    39   BOOST_STATIC_ASSERT(!std::numeric_limits<RealType>::is_integer);

    40 #endif

    41 

    42   explicit uniform_01(base_type rng)

    43     : _rng(rng),

    44       _factor(result_type(1) /

    45               (result_type((_rng.max)()-(_rng.min)()) +

    46                result_type(std::numeric_limits<base_result>::is_integer ? 1 : 0)))

    47   {

    48   }

    49   // compiler-generated copy ctor and copy assignment are fine

    50 

    51   result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(0); }

    52   result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(1); }

    53   base_type& base() { return _rng; }

    54   const base_type& base() const { return _rng; }

    55   void reset() { }

    56 

    57   result_type operator()() {

    58     return result_type(_rng() - (_rng.min)()) * _factor;

    59   }

    60 

    61 #if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)

    62   template<class CharT, class Traits>

    63   friend std::basic_ostream<CharT,Traits>&

    64   operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_01& u)

    65   {

    66     os << u._rng;

    67     return os;

    68   }

    69 

    70   template<class CharT, class Traits>

    71   friend std::basic_istream<CharT,Traits>&

    72   operator>>(std::basic_istream<CharT,Traits>& is, uniform_01& u)

    73   {

    74     is >> u._rng;

    75     return is;

    76   }

    77 #endif

    78 

    79 private:

    80   typedef typename base_type::result_type base_result;

    81   base_type _rng;

    82   result_type _factor;

    83 };

    84 

    85 #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION

    86 //  A definition is required even for integral static constants

    87 template<class UniformRandomNumberGenerator, class RealType>

    88 const bool uniform_01<UniformRandomNumberGenerator, RealType>::has_fixed_range;

    89 #endif

    90 

    91 } // namespace boost

    92 

    93 #endif // BOOST_RANDOM_UNIFORM_01_HPP