259 lines
9.0 KiB
C++
Executable File
259 lines
9.0 KiB
C++
Executable File
/* boost random/linear_congruential.hpp header file
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*
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* Copyright Jens Maurer 2000-2001
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* Distributed under the Boost Software License, Version 1.0. (See
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* accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* See http://www.boost.org for most recent version including documentation.
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*
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* $Id: linear_congruential.hpp 29116 2005-05-21 15:57:01Z dgregor $
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*
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* Revision history
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* 2001-02-18 moved to individual header files
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*/
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#ifndef BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP
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#define BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP
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#include <iostream>
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#include <cassert>
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#include <stdexcept>
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#include <boost/config.hpp>
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#include <boost/limits.hpp>
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#include <boost/static_assert.hpp>
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#include <boost/random/detail/const_mod.hpp>
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#include <boost/detail/workaround.hpp>
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namespace boost {
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namespace random {
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// compile-time configurable linear congruential generator
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template<class IntType, IntType a, IntType c, IntType m, IntType val>
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class linear_congruential
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{
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public:
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typedef IntType result_type;
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#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
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static const bool has_fixed_range = true;
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static const result_type min_value = ( c == 0 ? 1 : 0 );
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static const result_type max_value = m-1;
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#else
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BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
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#endif
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BOOST_STATIC_CONSTANT(IntType, multiplier = a);
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BOOST_STATIC_CONSTANT(IntType, increment = c);
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BOOST_STATIC_CONSTANT(IntType, modulus = m);
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// MSVC 6 and possibly others crash when encountering complicated integral
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// constant expressions. Avoid the check for now.
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// BOOST_STATIC_ASSERT(m == 0 || a < m);
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// BOOST_STATIC_ASSERT(m == 0 || c < m);
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explicit linear_congruential(IntType x0 = 1)
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: _modulus(modulus), _x(_modulus ? (x0 % _modulus) : x0)
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{
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assert(c || x0); /* if c == 0 and x(0) == 0 then x(n) = 0 for all n */
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// overflow check
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// disabled because it gives spurious "divide by zero" gcc warnings
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// assert(m == 0 || (a*(m-1)+c) % m == (c < a ? c-a+m : c-a));
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// MSVC fails BOOST_STATIC_ASSERT with std::numeric_limits at class scope
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#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
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BOOST_STATIC_ASSERT(std::numeric_limits<IntType>::is_integer);
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#endif
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}
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template<class It>
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linear_congruential(It& first, It last) { seed(first, last); }
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// compiler-generated copy constructor and assignment operator are fine
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void seed(IntType x0 = 1)
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{
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assert(c || x0);
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_x = (_modulus ? (x0 % _modulus) : x0);
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}
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template<class It>
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void seed(It& first, It last)
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{
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if(first == last)
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throw std::invalid_argument("linear_congruential::seed");
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IntType value = *first++;
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_x = (_modulus ? (value % _modulus) : value);
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}
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result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return c == 0 ? 1 : 0; }
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result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return modulus-1; }
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IntType operator()()
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{
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_x = const_mod<IntType, m>::mult_add(a, _x, c);
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return _x;
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}
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static bool validation(IntType x) { return val == x; }
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#ifdef BOOST_NO_OPERATORS_IN_NAMESPACE
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// Use a member function; Streamable concept not supported.
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bool operator==(const linear_congruential& rhs) const
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{ return _x == rhs._x; }
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bool operator!=(const linear_congruential& rhs) const
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{ return !(*this == rhs); }
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#else
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friend bool operator==(const linear_congruential& x,
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const linear_congruential& y)
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{ return x._x == y._x; }
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friend bool operator!=(const linear_congruential& x,
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const linear_congruential& y)
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{ return !(x == y); }
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#if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) && !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
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template<class CharT, class Traits>
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friend std::basic_ostream<CharT,Traits>&
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operator<<(std::basic_ostream<CharT,Traits>& os,
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const linear_congruential& lcg)
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{
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return os << lcg._x;
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}
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template<class CharT, class Traits>
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friend std::basic_istream<CharT,Traits>&
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operator>>(std::basic_istream<CharT,Traits>& is,
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linear_congruential& lcg)
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{
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return is >> lcg._x;
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}
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private:
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#endif
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#endif
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IntType _modulus; // work-around for gcc "divide by zero" warning in ctor
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IntType _x;
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};
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// probably needs the "no native streams" caveat for STLPort
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#if !defined(__SGI_STL_PORT) && BOOST_WORKAROUND(__GNUC__, == 2)
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template<class IntType, IntType a, IntType c, IntType m, IntType val>
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std::ostream&
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operator<<(std::ostream& os,
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const linear_congruential<IntType,a,c,m,val>& lcg)
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{
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return os << lcg._x;
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}
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template<class IntType, IntType a, IntType c, IntType m, IntType val>
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std::istream&
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operator>>(std::istream& is,
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linear_congruential<IntType,a,c,m,val>& lcg)
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{
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return is >> lcg._x;
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}
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#elif defined(BOOST_NO_OPERATORS_IN_NAMESPACE) || defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
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template<class CharT, class Traits, class IntType, IntType a, IntType c, IntType m, IntType val>
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std::basic_ostream<CharT,Traits>&
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operator<<(std::basic_ostream<CharT,Traits>& os,
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const linear_congruential<IntType,a,c,m,val>& lcg)
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{
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return os << lcg._x;
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}
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template<class CharT, class Traits, class IntType, IntType a, IntType c, IntType m, IntType val>
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std::basic_istream<CharT,Traits>&
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operator>>(std::basic_istream<CharT,Traits>& is,
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linear_congruential<IntType,a,c,m,val>& lcg)
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{
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return is >> lcg._x;
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}
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#endif
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#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
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// A definition is required even for integral static constants
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template<class IntType, IntType a, IntType c, IntType m, IntType val>
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const bool linear_congruential<IntType, a, c, m, val>::has_fixed_range;
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template<class IntType, IntType a, IntType c, IntType m, IntType val>
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const typename linear_congruential<IntType, a, c, m, val>::result_type linear_congruential<IntType, a, c, m, val>::min_value;
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template<class IntType, IntType a, IntType c, IntType m, IntType val>
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const typename linear_congruential<IntType, a, c, m, val>::result_type linear_congruential<IntType, a, c, m, val>::max_value;
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template<class IntType, IntType a, IntType c, IntType m, IntType val>
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const IntType linear_congruential<IntType,a,c,m,val>::modulus;
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#endif
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} // namespace random
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// validation values from the publications
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typedef random::linear_congruential<int32_t, 16807, 0, 2147483647,
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1043618065> minstd_rand0;
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typedef random::linear_congruential<int32_t, 48271, 0, 2147483647,
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399268537> minstd_rand;
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#if !defined(BOOST_NO_INT64_T) && !defined(BOOST_NO_INTEGRAL_INT64_T)
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// emulate the lrand48() C library function; requires support for uint64_t
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class rand48
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{
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public:
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typedef int32_t result_type;
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#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
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static const bool has_fixed_range = true;
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static const int32_t min_value = 0;
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static const int32_t max_value = integer_traits<int32_t>::const_max;
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#else
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enum { has_fixed_range = false };
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#endif
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int32_t min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return 0; }
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int32_t max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return std::numeric_limits<int32_t>::max BOOST_PREVENT_MACRO_SUBSTITUTION (); }
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explicit rand48(int32_t x0 = 1) : lcf(cnv(x0)) { }
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explicit rand48(uint64_t x0) : lcf(x0) { }
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template<class It> rand48(It& first, It last) : lcf(first, last) { }
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// compiler-generated copy ctor and assignment operator are fine
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void seed(int32_t x0 = 1) { lcf.seed(cnv(x0)); }
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void seed(uint64_t x0) { lcf.seed(x0); }
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template<class It> void seed(It& first, It last) { lcf.seed(first,last); }
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int32_t operator()() { return static_cast<int32_t>(lcf() >> 17); }
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// by experiment from lrand48()
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static bool validation(int32_t x) { return x == 1993516219; }
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#ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
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#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
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template<class CharT,class Traits>
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friend std::basic_ostream<CharT,Traits>&
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operator<<(std::basic_ostream<CharT,Traits>& os, const rand48& r)
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{ os << r.lcf; return os; }
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template<class CharT,class Traits>
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friend std::basic_istream<CharT,Traits>&
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operator>>(std::basic_istream<CharT,Traits>& is, rand48& r)
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{ is >> r.lcf; return is; }
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#endif
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friend bool operator==(const rand48& x, const rand48& y)
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{ return x.lcf == y.lcf; }
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friend bool operator!=(const rand48& x, const rand48& y)
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{ return !(x == y); }
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#else
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// Use a member function; Streamable concept not supported.
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bool operator==(const rand48& rhs) const
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{ return lcf == rhs.lcf; }
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bool operator!=(const rand48& rhs) const
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{ return !(*this == rhs); }
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#endif
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private:
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random::linear_congruential<uint64_t,
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uint64_t(0xDEECE66DUL) | (uint64_t(0x5) << 32), // xxxxULL is not portable
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0xB, uint64_t(1)<<48, /* unknown */ 0> lcf;
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static uint64_t cnv(int32_t x)
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{ return (static_cast<uint64_t>(x) << 16) | 0x330e; }
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};
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#endif /* !BOOST_NO_INT64_T && !BOOST_NO_INTEGRAL_INT64_T */
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} // namespace boost
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#endif // BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP
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