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
|
// Copyright (c) 1997-2001 Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel). All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.2-branch/Random_numbers/include/CGAL/Random.h $
// $Id: Random.h 28567 2006-02-16 14:30:13Z lsaboret $
//
//
// Author(s) : Sven Schoenherr <sven@inf.ethz.ch>, Sylvain Pion
#ifndef CGAL_RANDOM_H
#define CGAL_RANDOM_H
#include <CGAL/basic.h>
CGAL_BEGIN_NAMESPACE
class Random {
public:
// creation
Random( );
Random( unsigned int seed);
// operations
bool get_bool ( );
int get_int ( int lower, int upper);
double get_double( double lower = 0.0, double upper = 1.0);
// Computes a random int value smaller than 2^b.
// It's supposed to be fast, useful for randomized algorithms.
// The distribution is not perfectly flat, but this is a sacrifice against
// efficiency.
template <int b>
int get_bits()
{
CGAL_assertion(0<b && b<16);
if (val == 0) {
random_value = (421U * random_value + 2073U) % 32749U;
val = random_value;
}
int ret = val & ((1<<b)-1);
val >>= 1; // Shifting by b would be slightly better, but is slower.
return ret;
}
int operator () ( int upper);
private:
// data members
const double rand_max_plus_1;
unsigned int random_value; // Current 15 bits random value.
unsigned int val; // random_value shifted by used bits.
};
// Global variables
// ================
extern Random default_random;
CGAL_END_NAMESPACE
// ============================================================================
// Class implementation (inline functions)
// =======================================
// includes
# include <cstdlib>
CGAL_BEGIN_NAMESPACE
// operations
inline
bool
Random::
get_bool( )
{
return( static_cast< bool>( CGAL_CLIB_STD::rand() & 1));
}
inline
int
Random::
get_int( int lower, int upper)
{
return( lower + static_cast< int>(
( static_cast< double>( upper) - lower) *
CGAL_CLIB_STD::rand() / rand_max_plus_1));
}
inline
double
Random::
get_double( double lower, double upper)
{
return( lower + ( ( upper-lower) *
CGAL_CLIB_STD::rand() / rand_max_plus_1));
}
inline
int
Random::
operator () ( int upper)
{
return( get_int( 0, upper));
}
CGAL_END_NAMESPACE
#endif // CGAL_RANDOM_H
// ===== EOF ==================================================================
|
