/* boost random/uniform_real.hpp header file | |
* | |
* Copyright Jens Maurer 2000-2001 | |
* Distributed under the Boost Software License, Version 1.0. (See | |
* accompanying file LICENSE_1_0.txt or copy at | |
* http://www.boost.org/LICENSE_1_0.txt) | |
* | |
* See http://www.boost.org for most recent version including documentation. | |
* | |
* $Id: uniform_real.hpp 60755 2010-03-22 00:45:06Z steven_watanabe $ | |
* | |
* Revision history | |
* 2001-04-08 added min<max assertion (N. Becker) | |
* 2001-02-18 moved to individual header files | |
*/ | |
#ifndef BOOST_RANDOM_UNIFORM_REAL_HPP | |
#define BOOST_RANDOM_UNIFORM_REAL_HPP | |
#include <cassert> | |
#include <iostream> | |
#include <boost/config.hpp> | |
#include <boost/limits.hpp> | |
#include <boost/static_assert.hpp> | |
#include <boost/random/detail/config.hpp> | |
namespace boost { | |
/** | |
* The distribution function uniform_real models a random distribution. | |
* On each invocation, it returns a random floating-point value uniformly | |
* distributed in the range [min..max). The value is computed using | |
* std::numeric_limits<RealType>::digits random binary digits, i.e. | |
* the mantissa of the floating-point value is completely filled with | |
* random bits. | |
* | |
* Note: The current implementation is buggy, because it may not fill | |
* all of the mantissa with random bits. | |
*/ | |
template<class RealType = double> | |
class uniform_real | |
{ | |
public: | |
typedef RealType input_type; | |
typedef RealType result_type; | |
/** | |
* Constructs a uniform_real object. @c min and @c max are the | |
* parameters of the distribution. | |
* | |
* Requires: min <= max | |
*/ | |
explicit uniform_real(RealType min_arg = RealType(0), | |
RealType max_arg = RealType(1)) | |
: _min(min_arg), _max(max_arg) | |
{ | |
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS | |
BOOST_STATIC_ASSERT(!std::numeric_limits<RealType>::is_integer); | |
#endif | |
assert(min_arg <= max_arg); | |
} | |
// compiler-generated copy ctor and assignment operator are fine | |
/** | |
* Returns: The "min" parameter of the distribution | |
*/ | |
result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return _min; } | |
/** | |
* Returns: The "max" parameter of the distribution | |
*/ | |
result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return _max; } | |
void reset() { } | |
template<class Engine> | |
result_type operator()(Engine& eng) { | |
result_type numerator = static_cast<result_type>(eng() - eng.min BOOST_PREVENT_MACRO_SUBSTITUTION()); | |
result_type divisor = static_cast<result_type>(eng.max BOOST_PREVENT_MACRO_SUBSTITUTION() - eng.min BOOST_PREVENT_MACRO_SUBSTITUTION()); | |
assert(divisor > 0); | |
assert(numerator >= 0 && numerator <= divisor); | |
return numerator / divisor * (_max - _min) + _min; | |
} | |
#ifndef BOOST_RANDOM_NO_STREAM_OPERATORS | |
template<class CharT, class Traits> | |
friend std::basic_ostream<CharT,Traits>& | |
operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_real& ud) | |
{ | |
os << ud._min << " " << ud._max; | |
return os; | |
} | |
template<class CharT, class Traits> | |
friend std::basic_istream<CharT,Traits>& | |
operator>>(std::basic_istream<CharT,Traits>& is, uniform_real& ud) | |
{ | |
is >> std::ws >> ud._min >> std::ws >> ud._max; | |
return is; | |
} | |
#endif | |
private: | |
RealType _min, _max; | |
}; | |
} // namespace boost | |
#endif // BOOST_RANDOM_UNIFORM_REAL_HPP |