boost/random/uniform_01.hpp
/* boost random/uniform_01.hpp header file
*
* Copyright Jens Maurer 2000-2001
* Permission to use, copy, modify, sell, and distribute this software
* is hereby granted without fee provided that the above copyright notice
* appears in all copies and that both that copyright notice and this
* permission notice appear in supporting documentation,
*
* Jens Maurer makes no representations about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*
* See http://www.boost.org for most recent version including documentation.
*
* $Id: uniform_01.hpp,v 1.15.2.1 2004/01/25 21:26:45 jmaurer Exp $
*
* Revision history
* 2001-02-18 moved to individual header files
*/
#ifndef BOOST_RANDOM_UNIFORM_01_HPP
#define BOOST_RANDOM_UNIFORM_01_HPP
#include <iostream>
#include <boost/config.hpp>
#include <boost/limits.hpp>
#include <boost/static_assert.hpp>
namespace boost {
// Because it is so commonly used: uniform distribution on the real [0..1)
// range. This allows for specializations to avoid a costly int -> float
// conversion plus float multiplication
template<class UniformRandomNumberGenerator, class RealType = double>
class uniform_01
{
public:
typedef UniformRandomNumberGenerator base_type;
typedef RealType result_type;
BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
#if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) && !(defined(BOOST_MSVC) && BOOST_MSVC <= 1300)
BOOST_STATIC_ASSERT(!std::numeric_limits<RealType>::is_integer);
#endif
explicit uniform_01(base_type rng)
: _rng(rng),
_factor(result_type(1) /
(result_type(_rng.max()-_rng.min()) +
result_type(std::numeric_limits<base_result>::is_integer ? 1 : 0)))
{
}
// compiler-generated copy ctor and copy assignment are fine
result_type min() const { return result_type(0); }
result_type max() const { return result_type(1); }
base_type& base() { return _rng; }
const base_type& base() const { return _rng; }
void reset() { }
result_type operator()() {
return result_type(_rng() - _rng.min()) * _factor;
}
#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
template<class CharT, class Traits>
friend std::basic_ostream<CharT,Traits>&
operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_01& u)
{
os << u._rng;
return os;
}
template<class CharT, class Traits>
friend std::basic_istream<CharT,Traits>&
operator>>(std::basic_istream<CharT,Traits>& is, uniform_01& u)
{
is >> u._rng;
return is;
}
#endif
private:
typedef typename base_type::result_type base_result;
base_type _rng;
result_type _factor;
};
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
// A definition is required even for integral static constants
template<class UniformRandomNumberGenerator, class RealType>
const bool uniform_01<UniformRandomNumberGenerator, RealType>::has_fixed_range;
#endif
} // namespace boost
#endif // BOOST_RANDOM_UNIFORM_01_HPP