/usr/include/boost/random
Edit: /usr/include/boost/random/uniform_01.hpp (7538B)
/* boost random/uniform_01.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.
*
* $Id$
*
* Revision history
* 2001-02-18 moved to individual header files
*/
#ifndef BOOST_RANDOM_UNIFORM_01_HPP
#define BOOST_RANDOM_UNIFORM_01_HPP
#include
#include
#include
#include
#include
#include
#include
namespace boost {
namespace random {
#ifdef BOOST_RANDOM_DOXYGEN
/**
* The distribution function uniform_01 models a \random_distribution.
* On each invocation, it returns a random floating-point value
* uniformly distributed in the range [0..1).
*
* The template parameter RealType shall denote a float-like value type
* with support for binary operators +, -, and /.
*
* Note: The current implementation is buggy, because it may not fill
* all of the mantissa with random bits. I'm unsure how to fill a
* (to-be-invented) @c boost::bigfloat class with random bits efficiently.
* It's probably time for a traits class.
*/
template
class uniform_01
{
public:
typedef RealType input_type;
typedef RealType result_type;
result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const;
result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const;
void reset();
template
result_type operator()(Engine& eng);
#ifndef BOOST_RANDOM_NO_STREAM_OPERATORS
template
friend std::basic_ostream&
operator<<(std::basic_ostream& os, const new_uniform_01&)
{
return os;
}
template
friend std::basic_istream&
operator>>(std::basic_istream& is, new_uniform_01&)
{
return is;
}
#endif
};
#else
namespace detail {
template
class new_uniform_01
{
public:
typedef RealType input_type;
typedef RealType result_type;
// compiler-generated copy ctor and copy assignment are fine
result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(0); }
result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(1); }
void reset() { }
template
result_type operator()(Engine& eng) {
for (;;) {
typedef typename Engine::result_type base_result;
result_type factor = result_type(1) /
(result_type(base_result((eng.max)()-(eng.min)())) +
result_type(std::numeric_limits::is_integer ? 1 : 0));
result_type result = result_type(base_result(eng() - (eng.min)())) * factor;
if (result < result_type(1))
return result;
}
}
#ifndef BOOST_RANDOM_NO_STREAM_OPERATORS
template
friend std::basic_ostream&
operator<<(std::basic_ostream& os, const new_uniform_01&)
{
return os;
}
template
friend std::basic_istream&
operator>>(std::basic_istream& is, new_uniform_01&)
{
return is;
}
#endif
};
template
class backward_compatible_uniform_01
{
typedef boost::random::detail::ptr_helper traits;
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)
BOOST_STATIC_ASSERT(!std::numeric_limits::is_integer);
#endif
explicit backward_compatible_uniform_01(typename traits::rvalue_type rng)
: _rng(rng),
_factor(result_type(1) /
(result_type((base().max)()-(base().min)()) +
result_type(std::numeric_limits::is_integer ? 1 : 0)))
{
}
// compiler-generated copy ctor and copy assignment are fine
result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(0); }
result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(1); }
typename traits::value_type& base() { return traits::ref(_rng); }
const typename traits::value_type& base() const { return traits::ref(_rng); }
void reset() { }
result_type operator()() {
for (;;) {
result_type result = result_type(base()() - (base().min)()) * _factor;
if (result < result_type(1))
return result;
}
}
#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
template
friend std::basic_ostream&
operator<<(std::basic_ostream& os, const backward_compatible_uniform_01& u)
{
os << u._rng;
return os;
}
template
friend std::basic_istream&
operator>>(std::basic_istream& is, backward_compatible_uniform_01& u)
{
is >> u._rng;
return is;
}
#endif
private:
typedef typename traits::value_type::result_type base_result;
UniformRandomNumberGenerator _rng;
result_type _factor;
};
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
// A definition is required even for integral static constants
template
const bool backward_compatible_uniform_01::has_fixed_range;
#endif
template::is_specialized>
struct select_uniform_01
{
template
struct apply
{
typedef backward_compatible_uniform_01 type;
};
};
template
struct select_uniform_01
{
template
struct apply
{
typedef new_uniform_01 type;
};
};
}
// 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 uniform_01
: public detail::select_uniform_01::BOOST_NESTED_TEMPLATE apply::type
{
typedef typename detail::select_uniform_01::BOOST_NESTED_TEMPLATE apply::type impl_type;
typedef boost::random::detail::ptr_helper traits;
public:
uniform_01() {}
explicit uniform_01(typename traits::rvalue_type rng)
: impl_type(rng)
{
}
#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
template
friend std::basic_ostream&
operator<<(std::basic_ostream& os, const uniform_01& u)
{
os << static_cast(u);
return os;
}
template
friend std::basic_istream&
operator>>(std::basic_istream& is, uniform_01& u)
{
is >> static_cast(u);
return is;
}
#endif
};
#endif
} // namespace random
using random::uniform_01;
} // namespace boost
#include
#endif // BOOST_RANDOM_UNIFORM_01_HPP