Imported existing code

libraries/include/boost/random/linear_congruential.hpp

@@ -0,0 +1,263 @@
+/* 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 52492 2009-04-19 14:55:57Z 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>
+
+namespace boost {
+namespace random {
+
+// compile-time configurable linear congruential generator
+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);
+
+  explicit linear_congruential(IntType x0 = 1)
+    : _modulus(modulus), _x(_modulus ? (x0 % _modulus) : x0)
+  { 
+    assert(c || x0); /* if c == 0 and x(0) == 0 then x(n) = 0 for all n */
+    // overflow check
+    // disabled because it gives spurious "divide by zero" gcc warnings
+    // assert(m == 0 || (a*(m-1)+c) % m == (c < a ? c-a+m : c-a)); 
+
+    // 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
+  }
+
+  template<class It>
+  linear_congruential(It& first, It last)
+    : _modulus(modulus)
+  {
+      seed(first, last);
+  }
+
+  // compiler-generated copy constructor and assignment operator are fine
+  void seed(IntType x0 = 1)
+  {
+    assert(c || x0);
+    _x = (_modulus ? (x0 % _modulus) : x0);
+  }
+
+  template<class It>
+  void seed(It& first, It last)
+  {
+    if(first == last)
+      throw std::invalid_argument("linear_congruential::seed");
+    IntType value = *first++;
+    _x = (_modulus ? (value % _modulus) : value);
+  }
+
+  result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return c == 0 ? 1 : 0; }
+  result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return modulus-1; }
+
+  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 _modulus;   // work-around for gcc "divide by zero" warning in ctor
+  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
+typedef random::linear_congruential<int32_t, 16807, 0, 2147483647, 
+  1043618065> minstd_rand0;
+typedef random::linear_congruential<int32_t, 48271, 0, 2147483647,
+  399268537> minstd_rand;
+
+
+#if !defined(BOOST_NO_INT64_T) && !defined(BOOST_NO_INTEGRAL_INT64_T)
+// emulate the lrand48() C library function; requires support for uint64_t
+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
+  int32_t min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return 0; }
+  int32_t max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return std::numeric_limits<int32_t>::max BOOST_PREVENT_MACRO_SUBSTITUTION (); }
+  
+  explicit rand48(int32_t x0 = 1) : lcf(cnv(x0)) { }
+  explicit rand48(uint64_t x0) : lcf(x0) { }
+  template<class It> rand48(It& first, It last) : lcf(first, last) { }
+  // compiler-generated copy ctor and assignment operator are fine
+  void seed(int32_t x0 = 1) { lcf.seed(cnv(x0)); }
+  void seed(uint64_t x0) { lcf.seed(x0); }
+  template<class It> void seed(It& first, It last) { lcf.seed(first,last); }
+
+  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:
+  random::linear_congruential<uint64_t,
+    uint64_t(0xDEECE66DUL) | (uint64_t(0x5) << 32), // xxxxULL is not portable
+    0xB, uint64_t(1)<<48, /* unknown */ 0> lcf;
+  static uint64_t cnv(int32_t x) 
+  { return (static_cast<uint64_t>(x) << 16) | 0x330e;  }
+};
+#endif /* !BOOST_NO_INT64_T && !BOOST_NO_INTEGRAL_INT64_T */
+
+} // namespace boost
+
+#endif // BOOST_RANDOM_LINEAR_CONGRUENTIAL_HPP