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random.hpp
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1 /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2 /*
3  * Main authors:
4  * Christian Schulte <schulte@gecode.org>
5  * Mikael Lagerkvist <lagerkvist@gecode.org>
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7  * Copyright:
8  * Christian Schulte, 2005
9  * Mikael Lagerkvist, 2005
10  *
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35 
36 namespace Gecode { namespace Support {
37 
45  template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
47  private:
49  static const unsigned int max = 1UL<<31;
51  unsigned int s;
53  unsigned int next(void);
54  public:
56  void seed(unsigned int s);
58  LinearCongruentialGenerator(unsigned int s = 1);
60  unsigned int seed(void) const;
62  unsigned int operator ()(unsigned int n);
64  size_t size(void) const;
65  };
66 
67  template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
68  forceinline unsigned int
70  s = a*(s%q) - r*(s/q);
71  unsigned int res = s;
72  if (s==0) s = 1;
73  return res;
74  }
75  template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
76  forceinline void
78  s = _s % m;
79  if (s == 0) s = 1;
80  }
81  template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
84  LinearCongruentialGenerator(unsigned int _s) {
85  seed(_s);
86  }
87  template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
88  forceinline unsigned int
90  return s;
91  }
92  template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
93  forceinline unsigned int
95  unsigned int x1 = next() & ((1<<16)-1);
96  unsigned int x2 = next() & ((1<<16)-1);
97  if (n < 2) return 0;
98  double d = static_cast<double>(((x1<<16) | x2) % max) / max;
99  unsigned int val = static_cast<unsigned int>(n * d);
100  return (val < n) ? val : (n-1);
101  }
102  template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
103  forceinline size_t
106  }
107 
108 
121 
122 }}
123 
124 // STATISTICS: support-any
void max(Home home, FloatVar x0, FloatVar x1, FloatVar x2)
Post propagator for .
Definition: arithmetic.cpp:49
unsigned int seed(void) const
Return current seed.
Definition: random.hpp:89
LinearCongruentialGenerator< 2147483647, 48271, 44488, 3399 > RandomGenerator
Default values for linear congruential generator.
Definition: random.hpp:120
LinearCongruentialGenerator(unsigned int s=1)
Construct the generator instance with seed s.
Definition: random.hpp:84
Gecode toplevel namespace
Post propagator for SetVar SetOpType SetVar SetRelType r
Definition: set.hh:767
Template for linear congruential generators.
Definition: random.hpp:46
struct Gecode::@602::NNF::@65::@67 a
For atomic nodes.
Gecode::IntSet d(v, 7)
size_t size(void) const
Report size occupied.
Definition: random.hpp:104
#define forceinline
Definition: config.hpp:185
int n
Number of negative literals for node type.
Definition: bool-expr.cpp:234
unsigned int operator()(unsigned int n)
Returns a random integer from the interval [0..n)
Definition: random.hpp:94