/usr/include/gecode/support/random.hpp is in libgecode-dev 4.4.0-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 | /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
* Main authors:
* Christian Schulte <schulte@gecode.org>
* Mikael Lagerkvist <lagerkvist@gecode.org>
*
* Copyright:
* Christian Schulte, 2005
* Mikael Lagerkvist, 2005
*
* Last modified:
* $Date: 2012-09-07 11:29:57 +0200 (Fri, 07 Sep 2012) $ by $Author: schulte $
* $Revision: 13061 $
*
* This file is part of Gecode, the generic constraint
* development environment:
* http://www.gecode.org
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
namespace Gecode { namespace Support {
/** \brief Template for linear congruential generators
*
* This class template defines a simple class for linear
* congruential generators.
*
* \ingroup FuncSupport
*/
template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
class LinearCongruentialGenerator {
private:
/// The maximum size of random numbers generated.
static const unsigned int max = 1UL<<31;
/// Current seed value
unsigned int s;
/// Generate next number in series
unsigned int next(void);
public:
/// Set the current seed to \a s
void seed(unsigned int s);
/// Construct the generator instance with seed \a s
LinearCongruentialGenerator(unsigned int s = 1);
/// Return current seed
unsigned int seed(void) const;
/// Returns a random integer from the interval [0..n)
unsigned int operator ()(unsigned int n);
/// Report size occupied
size_t size(void) const;
};
template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
forceinline unsigned int
LinearCongruentialGenerator<m,a,q,r>::next(void) {
s = a*(s%q) - r*(s/q);
unsigned int res = s;
if (s==0) s = 1;
return res;
}
template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
forceinline void
LinearCongruentialGenerator<m,a,q,r>::seed(unsigned int _s) {
s = _s % m;
if (s == 0) s = 1;
}
template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
forceinline
LinearCongruentialGenerator<m,a,q,r>::
LinearCongruentialGenerator(unsigned int _s) {
seed(_s);
}
template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
forceinline unsigned int
LinearCongruentialGenerator<m,a,q,r>::seed(void) const {
return s;
}
template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
forceinline unsigned int
LinearCongruentialGenerator<m,a,q,r>::operator ()(unsigned int n) {
unsigned int x1 = next() & ((1<<16)-1);
unsigned int x2 = next() & ((1<<16)-1);
if (n < 2) return 0;
double d = static_cast<double>(((x1<<16) | x2) % max) / max;
unsigned int val = static_cast<unsigned int>(n * d);
return (val < n) ? val : (n-1);
}
template<unsigned int m, unsigned int a, unsigned int q, unsigned int r>
forceinline size_t
LinearCongruentialGenerator<m,a,q,r>::size(void) const {
return sizeof(LinearCongruentialGenerator<m,a,q,r>);
}
/** \brief Default values for linear congruential generator
*
* While this pseudo-random number generator is not a good source of
* randomness, it is still an acceptable choice for many
* applications. The choice of values is taken from D. E. Knuth,
* The Art of Computer Programming, Vol 2, Seminumerical Algorithms,
* 3rd edition.
*
* \ingroup FuncSupport
*/
typedef LinearCongruentialGenerator<2147483647, 48271, 44488, 3399>
RandomGenerator;
}}
// STATISTICS: support-any
|