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/* 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
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