genesis-3d_engine/Engine/depends/boostWraper/boost/random/linear_congruential.hpp
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/* boost random/linear_congruential.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: linear_congruential.hpp 60755 2010-03-22 00:45:06Z steven_watanabe $
*
* Revision history
* 2001-02-18 moved to individual header files
*/
#ifndef BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP
#define BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP
#include <iostream>
#include <cassert>
#include <stdexcept>
#include <boost/config.hpp>
#include <boost/limits.hpp>
#include <boost/static_assert.hpp>
#include <boost/random/detail/config.hpp>
#include <boost/random/detail/const_mod.hpp>
#include <boost/detail/workaround.hpp>
#include <boost/random/detail/disable_warnings.hpp>
namespace boost {
namespace random {
/**
* Instantiations of class template linear_congruential model a
* \pseudo_random_number_generator. Linear congruential pseudo-random
* number generators are described in:
*
* "Mathematical methods in large-scale computing units", D. H. Lehmer,
* Proc. 2nd Symposium on Large-Scale Digital Calculating Machines,
* Harvard University Press, 1951, pp. 141-146
*
* Let x(n) denote the sequence of numbers returned by some pseudo-random
* number generator. Then for the linear congruential generator,
* x(n+1) := (a * x(n) + c) mod m. Parameters for the generator are
* x(0), a, c, m. The template parameter IntType shall denote an integral
* type. It must be large enough to hold values a, c, and m. The template
* parameters a and c must be smaller than m.
*
* Note: The quality of the generator crucially depends on the choice of
* the parameters. User code should use one of the sensibly parameterized
* generators such as minstd_rand instead.
*/
template<class IntType, IntType a, IntType c, IntType m, IntType val>
class linear_congruential
{
public:
typedef IntType result_type;
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
static const bool has_fixed_range = true;
static const result_type min_value = ( c == 0 ? 1 : 0 );
static const result_type max_value = m-1;
#else
BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
#endif
BOOST_STATIC_CONSTANT(IntType, multiplier = a);
BOOST_STATIC_CONSTANT(IntType, increment = c);
BOOST_STATIC_CONSTANT(IntType, modulus = m);
// MSVC 6 and possibly others crash when encountering complicated integral
// constant expressions. Avoid the check for now.
// BOOST_STATIC_ASSERT(m == 0 || a < m);
// BOOST_STATIC_ASSERT(m == 0 || c < m);
/**
* Constructs a linear_congruential generator, seeding it with @c x0.
*/
explicit linear_congruential(IntType x0 = 1)
{
seed(x0);
// MSVC fails BOOST_STATIC_ASSERT with std::numeric_limits at class scope
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
BOOST_STATIC_ASSERT(std::numeric_limits<IntType>::is_integer);
#endif
}
/**
* Constructs a @c linear_congruential generator and seeds it
* with values taken from the itrator range [first, last)
* and adjusts first to point to the element after the last one
* used. If there are not enough elements, throws @c std::invalid_argument.
*
* first and last must be input iterators.
*/
template<class It>
linear_congruential(It& first, It last)
{
seed(first, last);
}
// compiler-generated copy constructor and assignment operator are fine
/**
* If c mod m is zero and x0 mod m is zero, changes the current value of
* the generator to 1. Otherwise, changes it to x0 mod m. If c is zero,
* distinct seeds in the range [1,m) will leave the generator in distinct
* states. If c is not zero, the range is [0,m).
*/
void seed(IntType x0 = 1)
{
// wrap _x if it doesn't fit in the destination
if(modulus == 0) {
_x = x0;
} else {
_x = x0 % modulus;
}
// handle negative seeds
if(_x <= 0 && _x != 0) {
_x += modulus;
}
// adjust to the correct range
if(increment == 0 && _x == 0) {
_x = 1;
}
assert(_x >= (min)());
assert(_x <= (max)());
}
/**
* seeds a @c linear_congruential generator with values taken
* from the itrator range [first, last) and adjusts @c first to
* point to the element after the last one used. If there are
* not enough elements, throws @c std::invalid_argument.
*
* @c first and @c last must be input iterators.
*/
template<class It>
void seed(It& first, It last)
{
if(first == last)
throw std::invalid_argument("linear_congruential::seed");
seed(*first++);
}
/**
* Returns the smallest value that the @c linear_congruential generator
* can produce.
*/
result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return c == 0 ? 1 : 0; }
/**
* Returns the largest value that the @c linear_congruential generator
* can produce.
*/
result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return modulus-1; }
/** Returns the next value of the @c linear_congruential generator. */
IntType operator()()
{
_x = const_mod<IntType, m>::mult_add(a, _x, c);
return _x;
}
static bool validation(IntType x) { return val == x; }
#ifdef BOOST_NO_OPERATORS_IN_NAMESPACE
// Use a member function; Streamable concept not supported.
bool operator==(const linear_congruential& rhs) const
{ return _x == rhs._x; }
bool operator!=(const linear_congruential& rhs) const
{ return !(*this == rhs); }
#else
friend bool operator==(const linear_congruential& x,
const linear_congruential& y)
{ return x._x == y._x; }
friend bool operator!=(const linear_congruential& x,
const linear_congruential& y)
{ return !(x == y); }
#if !defined(BOOST_RANDOM_NO_STREAM_OPERATORS) && !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
template<class CharT, class Traits>
friend std::basic_ostream<CharT,Traits>&
operator<<(std::basic_ostream<CharT,Traits>& os,
const linear_congruential& lcg)
{
return os << lcg._x;
}
template<class CharT, class Traits>
friend std::basic_istream<CharT,Traits>&
operator>>(std::basic_istream<CharT,Traits>& is,
linear_congruential& lcg)
{
return is >> lcg._x;
}
private:
#endif
#endif
IntType _x;
};
// probably needs the "no native streams" caveat for STLPort
#if !defined(__SGI_STL_PORT) && BOOST_WORKAROUND(__GNUC__, == 2)
template<class IntType, IntType a, IntType c, IntType m, IntType val>
std::ostream&
operator<<(std::ostream& os,
const linear_congruential<IntType,a,c,m,val>& lcg)
{
return os << lcg._x;
}
template<class IntType, IntType a, IntType c, IntType m, IntType val>
std::istream&
operator>>(std::istream& is,
linear_congruential<IntType,a,c,m,val>& lcg)
{
return is >> lcg._x;
}
#elif defined(BOOST_RANDOM_NO_STREAM_OPERATORS) || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
template<class CharT, class Traits, class IntType, IntType a, IntType c, IntType m, IntType val>
std::basic_ostream<CharT,Traits>&
operator<<(std::basic_ostream<CharT,Traits>& os,
const linear_congruential<IntType,a,c,m,val>& lcg)
{
return os << lcg._x;
}
template<class CharT, class Traits, class IntType, IntType a, IntType c, IntType m, IntType val>
std::basic_istream<CharT,Traits>&
operator>>(std::basic_istream<CharT,Traits>& is,
linear_congruential<IntType,a,c,m,val>& lcg)
{
return is >> lcg._x;
}
#endif
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
// A definition is required even for integral static constants
template<class IntType, IntType a, IntType c, IntType m, IntType val>
const bool linear_congruential<IntType, a, c, m, val>::has_fixed_range;
template<class IntType, IntType a, IntType c, IntType m, IntType val>
const typename linear_congruential<IntType, a, c, m, val>::result_type linear_congruential<IntType, a, c, m, val>::min_value;
template<class IntType, IntType a, IntType c, IntType m, IntType val>
const typename linear_congruential<IntType, a, c, m, val>::result_type linear_congruential<IntType, a, c, m, val>::max_value;
template<class IntType, IntType a, IntType c, IntType m, IntType val>
const IntType linear_congruential<IntType,a,c,m,val>::modulus;
#endif
} // namespace random
// validation values from the publications
/**
* The specialization \minstd_rand0 was originally suggested in
*
* @blockquote
* A pseudo-random number generator for the System/360, P.A. Lewis,
* A.S. Goodman, J.M. Miller, IBM Systems Journal, Vol. 8, No. 2,
* 1969, pp. 136-146
* @endblockquote
*
* It is examined more closely together with \minstd_rand in
*
* @blockquote
* "Random Number Generators: Good ones are hard to find",
* Stephen K. Park and Keith W. Miller, Communications of
* the ACM, Vol. 31, No. 10, October 1988, pp. 1192-1201
* @endblockquote
*/
typedef random::linear_congruential<int32_t, 16807, 0, 2147483647,
1043618065> minstd_rand0;
/** The specialization \minstd_rand was suggested in
*
* @blockquote
* "Random Number Generators: Good ones are hard to find",
* Stephen K. Park and Keith W. Miller, Communications of
* the ACM, Vol. 31, No. 10, October 1988, pp. 1192-1201
* @endblockquote
*/
typedef random::linear_congruential<int32_t, 48271, 0, 2147483647,
399268537> minstd_rand;
#if !defined(BOOST_NO_INT64_T) && !defined(BOOST_NO_INTEGRAL_INT64_T)
/** Class @c rand48 models a \pseudo_random_number_generator. It uses
* the linear congruential algorithm with the parameters a = 0x5DEECE66D,
* c = 0xB, m = 2**48. It delivers identical results to the @c lrand48()
* function available on some systems (assuming lcong48 has not been called).
*
* It is only available on systems where @c uint64_t is provided as an
* integral type, so that for example static in-class constants and/or
* enum definitions with large @c uint64_t numbers work.
*/
class rand48
{
public:
typedef int32_t result_type;
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
static const bool has_fixed_range = true;
static const int32_t min_value = 0;
static const int32_t max_value = integer_traits<int32_t>::const_max;
#else
enum { has_fixed_range = false };
#endif
/**
* Returns the smallest value that the generator can produce
*/
int32_t min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return 0; }
/**
* Returns the largest value that the generator can produce
*/
int32_t max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return std::numeric_limits<int32_t>::max BOOST_PREVENT_MACRO_SUBSTITUTION (); }
#ifdef BOOST_RANDOM_DOXYGEN
/**
* If T is an integral type smaller than int46_t, constructs
* a \rand48 generator with x(0) := (x0 << 16) | 0x330e. Otherwise
* constructs a \rand48 generator with x(0) = x0.
*/
template<class T> explicit rand48(T x0 = 1);
#else
rand48() : lcf(cnv(static_cast<int32_t>(1))) {}
template<class T> explicit rand48(T x0) : lcf(cnv(x0)) { }
#endif
template<class It> rand48(It& first, It last) : lcf(first, last) { }
// compiler-generated copy ctor and assignment operator are fine
#ifdef BOOST_RANDOM_DOXYGEN
/**
* If T is an integral type smaller than int46_t, changes
* the current value x(n) of the generator to (x0 << 16) | 0x330e.
* Otherwise changes the current value x(n) to x0.
*/
template<class T> void seed(T x0 = 1);
#else
void seed() { seed(static_cast<int32_t>(1)); }
template<class T> void seed(T x0) { lcf.seed(cnv(x0)); }
#endif
template<class It> void seed(It& first, It last) { lcf.seed(first,last); }
/**
* Returns the next value of the generator.
*/
int32_t operator()() { return static_cast<int32_t>(lcf() >> 17); }
// by experiment from lrand48()
static bool validation(int32_t x) { return x == 1993516219; }
#ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
#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 rand48& r)
{ os << r.lcf; return os; }
template<class CharT,class Traits>
friend std::basic_istream<CharT,Traits>&
operator>>(std::basic_istream<CharT,Traits>& is, rand48& r)
{ is >> r.lcf; return is; }
#endif
friend bool operator==(const rand48& x, const rand48& y)
{ return x.lcf == y.lcf; }
friend bool operator!=(const rand48& x, const rand48& y)
{ return !(x == y); }
#else
// Use a member function; Streamable concept not supported.
bool operator==(const rand48& rhs) const
{ return lcf == rhs.lcf; }
bool operator!=(const rand48& rhs) const
{ return !(*this == rhs); }
#endif
private:
/// \cond hide_private_members
random::linear_congruential<uint64_t,
uint64_t(0xDEECE66DUL) | (uint64_t(0x5) << 32), // xxxxULL is not portable
0xB, uint64_t(1)<<48, /* unknown */ 0> lcf;
template<class T>
static uint64_t cnv(T x)
{
if(sizeof(T) < sizeof(uint64_t)) {
return (static_cast<uint64_t>(x) << 16) | 0x330e;
} else {
return(static_cast<uint64_t>(x));
}
}
static uint64_t cnv(float x) { return(static_cast<uint64_t>(x)); }
static uint64_t cnv(double x) { return(static_cast<uint64_t>(x)); }
static uint64_t cnv(long double x) { return(static_cast<uint64_t>(x)); }
/// \endcond
};
#endif /* !BOOST_NO_INT64_T && !BOOST_NO_INTEGRAL_INT64_T */
} // namespace boost
#include <boost/random/detail/enable_warnings.hpp>
#endif // BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP