1 /***********************************************************************
2 * Software License Agreement (BSD License)
3 *
4 * Copyright 2008-2009 Marius Muja (mariusm@cs.ubc.ca). All rights reserved.
5 * Copyright 2008-2009 David G. Lowe (lowe@cs.ubc.ca). All rights reserved.
6 *
7 * THE BSD LICENSE
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
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12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
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29 *************************************************************************/
30
31 #ifndef OPENCV_FLANN_RANDOM_H
32 #define OPENCV_FLANN_RANDOM_H
33
34 #include <algorithm>
35 #include <cstdlib>
36 #include <vector>
37
38 #include "general.h"
39
40 namespace cvflann
41 {
42
rand()43 inline int rand()
44 {
45 #ifndef OPENCV_FLANN_USE_STD_RAND
46 # if INT_MAX == RAND_MAX
47 int v = cv::theRNG().next() & INT_MAX;
48 # else
49 int v = cv::theRNG().uniform(0, RAND_MAX + 1);
50 # endif
51 #else
52 int v = std::rand();
53 #endif // OPENCV_FLANN_USE_STD_RAND
54 return v;
55 }
56
57 /**
58 * Seeds the random number generator
59 * @param seed Random seed
60 */
seed_random(unsigned int seed)61 inline void seed_random(unsigned int seed)
62 {
63 #ifndef OPENCV_FLANN_USE_STD_RAND
64 cv::theRNG() = cv::RNG(seed);
65 #else
66 std::srand(seed);
67 #endif
68 }
69
70 /*
71 * Generates a random double value.
72 */
73 /**
74 * Generates a random double value.
75 * @param high Upper limit
76 * @param low Lower limit
77 * @return Random double value
78 */
79 inline double rand_double(double high = 1.0, double low = 0)
80 {
81 return low + ((high-low) * (rand() / (RAND_MAX + 1.0)));
82 }
83
84 /**
85 * Generates a random integer value.
86 * @param high Upper limit
87 * @param low Lower limit
88 * @return Random integer value
89 */
90 inline int rand_int(int high = RAND_MAX, int low = 0)
91 {
92 return low + (int) ( double(high-low) * (rand() / (RAND_MAX + 1.0)));
93 }
94
95 /**
96 * Random number generator that returns a distinct number from
97 * the [0,n) interval each time.
98 */
99 class UniqueRandom
100 {
101 std::vector<int> vals_;
102 int size_;
103 int counter_;
104
105 public:
106 /**
107 * Constructor.
108 * @param n Size of the interval from which to generate
109 * @return
110 */
UniqueRandom(int n)111 UniqueRandom(int n)
112 {
113 init(n);
114 }
115
116 /**
117 * Initializes the number generator.
118 * @param n the size of the interval from which to generate random numbers.
119 */
init(int n)120 void init(int n)
121 {
122 // create and initialize an array of size n
123 vals_.resize(n);
124 size_ = n;
125 for (int i = 0; i < size_; ++i) vals_[i] = i;
126
127 // shuffle the elements in the array
128 #ifndef OPENCV_FLANN_USE_STD_RAND
129 cv::randShuffle(vals_);
130 #else
131 std::random_shuffle(vals_.begin(), vals_.end());
132 #endif
133
134 counter_ = 0;
135 }
136
137 /**
138 * Return a distinct random integer in greater or equal to 0 and less
139 * than 'n' on each call. It should be called maximum 'n' times.
140 * Returns: a random integer
141 */
next()142 int next()
143 {
144 if (counter_ == size_) {
145 return -1;
146 }
147 else {
148 return vals_[counter_++];
149 }
150 }
151 };
152
153 }
154
155 #endif //OPENCV_FLANN_RANDOM_H
156