boost/random/uniform_real.hpp

   1 /* boost random/uniform_real.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  * $Id$
  11  *
  12  * Revision history
  13  *  2001-04-08  added min<max assertion (N. Becker)
  14  *  2001-02-18  moved to individual header files
  15  */
  16
  17 #ifndef BOOST_RANDOM_UNIFORM_REAL_HPP
  18 #define BOOST_RANDOM_UNIFORM_REAL_HPP
  19
  20 #include <cassert>
  21 #include <iostream>
  22 #include <boost/config.hpp>
  23 #include <boost/limits.hpp>
  24 #include <boost/static_assert.hpp>
  25 #include <boost/random/detail/config.hpp>
  26
  27 namespace boost {
  28
  29 // uniform distribution on a real range
  30 template<class RealType = double>
  31 class uniform_real
  32 {
  33 public:
  34   typedef RealType input_type;
  35   typedef RealType result_type;
  36
  37   explicit uniform_real(RealType min_arg = RealType(0),
  38                         RealType max_arg = RealType(1))
  39     : _min(min_arg), _max(max_arg)
  40   {
  41 #ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
  42     BOOST_STATIC_ASSERT(!std::numeric_limits<RealType>::is_integer);
  43 #endif
  44     assert(min_arg <= max_arg);
  45   }
  46
  47   // compiler-generated copy ctor and assignment operator are fine
  48
  49   result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return _min; }
  50   result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return _max; }
  51   void reset() { }
  52
  53   template<class Engine>
  54   result_type operator()(Engine& eng) {
  55     return static_cast<result_type>(eng() - eng.min BOOST_PREVENT_MACRO_SUBSTITUTION())
  56            / static_cast<result_type>(eng.max BOOST_PREVENT_MACRO_SUBSTITUTION() - eng.min BOOST_PREVENT_MACRO_SUBSTITUTION())
  57            * (_max - _min) + _min;
  58   }
  59
  60 #ifndef BOOST_RANDOM_NO_STREAM_OPERATORS
  61   template<class CharT, class Traits>
  62   friend std::basic_ostream<CharT,Traits>&
  63   operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_real& ud)
  64   {
  65     os << ud._min << " " << ud._max;
  66     return os;
  67   }
  68
  69   template<class CharT, class Traits>
  70   friend std::basic_istream<CharT,Traits>&
  71   operator>>(std::basic_istream<CharT,Traits>& is, uniform_real& ud)
  72   {
  73     is >> std::ws >> ud._min >> std::ws >> ud._max;
  74     return is;
  75   }
  76 #endif
  77
  78 private:
  79   RealType _min, _max;
  80 };
  81
  82 } // namespace boost
  83
  84 #endif // BOOST_RANDOM_UNIFORM_REAL_HPP