epoc32/include/stdapis/boost/random/linear_congruential.hpp
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:33:34 +0100
branchSymbian3
changeset 4 837f303aceeb
permissions -rw-r--r--
Current Symbian^3 public API header files (from PDK 3.0.h)
This is the epoc32/include tree with the "platform" subtrees removed, and
all but a selected few mbg and rsg files removed.
     1 /* boost random/linear_congruential.hpp header file
     2  *
     3  * Copyright Jens Maurer 2000-2001
     4  * Distributed under the Boost Software License, Version 1.0. (See
     5  * accompanying file LICENSE_1_0.txt or copy at
     6  * http://www.boost.org/LICENSE_1_0.txt)
     7  *
     8  * See http://www.boost.org for most recent version including documentation.
     9  *
    10  * $Id: linear_congruential.hpp,v 1.22 2005/05/21 15:57:00 dgregor Exp $
    11  *
    12  * Revision history
    13  *  2001-02-18  moved to individual header files
    14  */
    15 
    16 #ifndef BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP
    17 #define BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP
    18 
    19 #include <iostream>
    20 #include <cassert>
    21 #include <stdexcept>
    22 #include <boost/config.hpp>
    23 #include <boost/limits.hpp>
    24 #include <boost/static_assert.hpp>
    25 #include <boost/random/detail/const_mod.hpp>
    26 #include <boost/detail/workaround.hpp>
    27 
    28 namespace boost {
    29 namespace random {
    30 
    31 // compile-time configurable linear congruential generator
    32 template<class IntType, IntType a, IntType c, IntType m, IntType val>
    33 class linear_congruential
    34 {
    35 public:
    36   typedef IntType result_type;
    37 #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
    38   static const bool has_fixed_range = true;
    39   static const result_type min_value = ( c == 0 ? 1 : 0 );
    40   static const result_type max_value = m-1;
    41 #else
    42   BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
    43 #endif
    44   BOOST_STATIC_CONSTANT(IntType, multiplier = a);
    45   BOOST_STATIC_CONSTANT(IntType, increment = c);
    46   BOOST_STATIC_CONSTANT(IntType, modulus = m);
    47 
    48   // MSVC 6 and possibly others crash when encountering complicated integral
    49   // constant expressions.  Avoid the check for now.
    50   // BOOST_STATIC_ASSERT(m == 0 || a < m);
    51   // BOOST_STATIC_ASSERT(m == 0 || c < m);
    52 
    53   explicit linear_congruential(IntType x0 = 1)
    54     : _modulus(modulus), _x(_modulus ? (x0 % _modulus) : x0)
    55   { 
    56     assert(c || x0); /* if c == 0 and x(0) == 0 then x(n) = 0 for all n */
    57     // overflow check
    58     // disabled because it gives spurious "divide by zero" gcc warnings
    59     // assert(m == 0 || (a*(m-1)+c) % m == (c < a ? c-a+m : c-a)); 
    60 
    61     // MSVC fails BOOST_STATIC_ASSERT with std::numeric_limits at class scope
    62 #ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
    63     BOOST_STATIC_ASSERT(std::numeric_limits<IntType>::is_integer);
    64 #endif
    65   }
    66 
    67   template<class It>
    68   linear_congruential(It& first, It last) { seed(first, last); }
    69 
    70   // compiler-generated copy constructor and assignment operator are fine
    71   void seed(IntType x0 = 1)
    72   {
    73     assert(c || x0);
    74     _x = (_modulus ? (x0 % _modulus) : x0);
    75   }
    76 
    77   template<class It>
    78   void seed(It& first, It last)
    79   {
    80     if(first == last)
    81       throw std::invalid_argument("linear_congruential::seed");
    82     IntType value = *first++;
    83     _x = (_modulus ? (value % _modulus) : value);
    84   }
    85 
    86   result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return c == 0 ? 1 : 0; }
    87   result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return modulus-1; }
    88 
    89   IntType operator()()
    90   {
    91     _x = const_mod<IntType, m>::mult_add(a, _x, c);
    92     return _x;
    93   }
    94 
    95   static bool validation(IntType x) { return val == x; }
    96 
    97 #ifdef BOOST_NO_OPERATORS_IN_NAMESPACE
    98     
    99   // Use a member function; Streamable concept not supported.
   100   bool operator==(const linear_congruential& rhs) const
   101   { return _x == rhs._x; }
   102   bool operator!=(const linear_congruential& rhs) const
   103   { return !(*this == rhs); }
   104 
   105 #else 
   106   friend bool operator==(const linear_congruential& x,
   107                          const linear_congruential& y)
   108   { return x._x == y._x; }
   109   friend bool operator!=(const linear_congruential& x,
   110                          const linear_congruential& y)
   111   { return !(x == y); }
   112     
   113 #if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) && !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
   114   template<class CharT, class Traits>
   115   friend std::basic_ostream<CharT,Traits>&
   116   operator<<(std::basic_ostream<CharT,Traits>& os,
   117              const linear_congruential& lcg)
   118   {
   119     return os << lcg._x;
   120   }
   121 
   122   template<class CharT, class Traits>
   123   friend std::basic_istream<CharT,Traits>&
   124   operator>>(std::basic_istream<CharT,Traits>& is,
   125              linear_congruential& lcg)
   126   {
   127     return is >> lcg._x;
   128   }
   129  
   130 private:
   131 #endif
   132 #endif
   133     
   134   IntType _modulus;   // work-around for gcc "divide by zero" warning in ctor
   135   IntType _x;
   136 };
   137 
   138 // probably needs the "no native streams" caveat for STLPort
   139 #if !defined(__SGI_STL_PORT) && BOOST_WORKAROUND(__GNUC__, == 2)
   140 template<class IntType, IntType a, IntType c, IntType m, IntType val>
   141 std::ostream&
   142 operator<<(std::ostream& os,
   143            const linear_congruential<IntType,a,c,m,val>& lcg)
   144 {
   145     return os << lcg._x;
   146 }
   147 
   148 template<class IntType, IntType a, IntType c, IntType m, IntType val>
   149 std::istream&
   150 operator>>(std::istream& is,
   151            linear_congruential<IntType,a,c,m,val>& lcg)
   152 {
   153     return is >> lcg._x;
   154 }
   155 #elif defined(BOOST_NO_OPERATORS_IN_NAMESPACE) || defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
   156 template<class CharT, class Traits, class IntType, IntType a, IntType c, IntType m, IntType val>
   157 std::basic_ostream<CharT,Traits>&
   158 operator<<(std::basic_ostream<CharT,Traits>& os,
   159            const linear_congruential<IntType,a,c,m,val>& lcg)
   160 {
   161     return os << lcg._x;
   162 }
   163 
   164 template<class CharT, class Traits, class IntType, IntType a, IntType c, IntType m, IntType val>
   165 std::basic_istream<CharT,Traits>&
   166 operator>>(std::basic_istream<CharT,Traits>& is,
   167            linear_congruential<IntType,a,c,m,val>& lcg)
   168 {
   169     return is >> lcg._x;
   170 }
   171 #endif
   172 
   173 #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
   174 //  A definition is required even for integral static constants
   175 template<class IntType, IntType a, IntType c, IntType m, IntType val>
   176 const bool linear_congruential<IntType, a, c, m, val>::has_fixed_range;
   177 template<class IntType, IntType a, IntType c, IntType m, IntType val>
   178 const typename linear_congruential<IntType, a, c, m, val>::result_type linear_congruential<IntType, a, c, m, val>::min_value;
   179 template<class IntType, IntType a, IntType c, IntType m, IntType val>
   180 const typename linear_congruential<IntType, a, c, m, val>::result_type linear_congruential<IntType, a, c, m, val>::max_value;
   181 template<class IntType, IntType a, IntType c, IntType m, IntType val>
   182 const IntType linear_congruential<IntType,a,c,m,val>::modulus;
   183 #endif
   184 
   185 } // namespace random
   186 
   187 // validation values from the publications
   188 typedef random::linear_congruential<int32_t, 16807, 0, 2147483647, 
   189   1043618065> minstd_rand0;
   190 typedef random::linear_congruential<int32_t, 48271, 0, 2147483647,
   191   399268537> minstd_rand;
   192 
   193 
   194 #if !defined(BOOST_NO_INT64_T) && !defined(BOOST_NO_INTEGRAL_INT64_T)
   195 // emulate the lrand48() C library function; requires support for uint64_t
   196 class rand48 
   197 {
   198 public:
   199   typedef int32_t result_type;
   200 #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
   201   static const bool has_fixed_range = true;
   202   static const int32_t min_value = 0;
   203   static const int32_t max_value = integer_traits<int32_t>::const_max;
   204 #else
   205   enum { has_fixed_range = false };
   206 #endif
   207   int32_t min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return 0; }
   208   int32_t max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return std::numeric_limits<int32_t>::max BOOST_PREVENT_MACRO_SUBSTITUTION (); }
   209   
   210   explicit rand48(int32_t x0 = 1) : lcf(cnv(x0)) { }
   211   explicit rand48(uint64_t x0) : lcf(x0) { }
   212   template<class It> rand48(It& first, It last) : lcf(first, last) { }
   213   // compiler-generated copy ctor and assignment operator are fine
   214   void seed(int32_t x0 = 1) { lcf.seed(cnv(x0)); }
   215   void seed(uint64_t x0) { lcf.seed(x0); }
   216   template<class It> void seed(It& first, It last) { lcf.seed(first,last); }
   217 
   218   int32_t operator()() { return static_cast<int32_t>(lcf() >> 17); }
   219   // by experiment from lrand48()
   220   static bool validation(int32_t x) { return x == 1993516219; }
   221 
   222 #ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
   223 
   224 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
   225   template<class CharT,class Traits>
   226   friend std::basic_ostream<CharT,Traits>&
   227   operator<<(std::basic_ostream<CharT,Traits>& os, const rand48& r)
   228   { os << r.lcf; return os; }
   229 
   230   template<class CharT,class Traits>
   231   friend std::basic_istream<CharT,Traits>&
   232   operator>>(std::basic_istream<CharT,Traits>& is, rand48& r)
   233   { is >> r.lcf; return is; }
   234 #endif
   235 
   236   friend bool operator==(const rand48& x, const rand48& y)
   237   { return x.lcf == y.lcf; }
   238   friend bool operator!=(const rand48& x, const rand48& y)
   239   { return !(x == y); }
   240 #else
   241   // Use a member function; Streamable concept not supported.
   242   bool operator==(const rand48& rhs) const
   243   { return lcf == rhs.lcf; }
   244   bool operator!=(const rand48& rhs) const
   245   { return !(*this == rhs); }
   246 #endif
   247 private:
   248   random::linear_congruential<uint64_t,
   249     uint64_t(0xDEECE66DUL) | (uint64_t(0x5) << 32), // xxxxULL is not portable
   250     0xB, uint64_t(1)<<48, /* unknown */ 0> lcf;
   251   static uint64_t cnv(int32_t x) 
   252   { return (static_cast<uint64_t>(x) << 16) | 0x330e;  }
   253 };
   254 #endif /* !BOOST_NO_INT64_T && !BOOST_NO_INTEGRAL_INT64_T */
   255 
   256 } // namespace boost
   257 
   258 #endif // BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP