Diff: include/opencv2/flann/random.h

Revision:

0:0e0631af0305

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/opencv2/flann/random.h	Fri Jan 29 04:53:38 2021 +0000
@@ -0,0 +1,133 @@
+/***********************************************************************
+ * Software License Agreement (BSD License)
+ *
+ * Copyright 2008-2009  Marius Muja (mariusm@cs.ubc.ca). All rights reserved.
+ * Copyright 2008-2009  David G. Lowe (lowe@cs.ubc.ca). All rights reserved.
+ *
+ * THE BSD LICENSE
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *************************************************************************/
+
+#ifndef OPENCV_FLANN_RANDOM_H
+#define OPENCV_FLANN_RANDOM_H
+
+#include <algorithm>
+#include <cstdlib>
+#include <vector>
+
+#include "general.h"
+
+namespace cvflann
+{
+
+/**
+ * Seeds the random number generator
+ *  @param seed Random seed
+ */
+inline void seed_random(unsigned int seed)
+{
+    srand(seed);
+}
+
+/*
+ * Generates a random double value.
+ */
+/**
+ * Generates a random double value.
+ * @param high Upper limit
+ * @param low Lower limit
+ * @return Random double value
+ */
+inline double rand_double(double high = 1.0, double low = 0)
+{
+    return low + ((high-low) * (std::rand() / (RAND_MAX + 1.0)));
+}
+
+/**
+ * Generates a random integer value.
+ * @param high Upper limit
+ * @param low Lower limit
+ * @return Random integer value
+ */
+inline int rand_int(int high = RAND_MAX, int low = 0)
+{
+    return low + (int) ( double(high-low) * (std::rand() / (RAND_MAX + 1.0)));
+}
+
+/**
+ * Random number generator that returns a distinct number from
+ * the [0,n) interval each time.
+ */
+class UniqueRandom
+{
+    std::vector<int> vals_;
+    int size_;
+    int counter_;
+
+public:
+    /**
+     * Constructor.
+     * @param n Size of the interval from which to generate
+     * @return
+     */
+    UniqueRandom(int n)
+    {
+        init(n);
+    }
+
+    /**
+     * Initializes the number generator.
+     * @param n the size of the interval from which to generate random numbers.
+     */
+    void init(int n)
+    {
+        // create and initialize an array of size n
+        vals_.resize(n);
+        size_ = n;
+        for (int i = 0; i < size_; ++i) vals_[i] = i;
+
+        // shuffle the elements in the array
+        std::random_shuffle(vals_.begin(), vals_.end());
+
+        counter_ = 0;
+    }
+
+    /**
+     * Return a distinct random integer in greater or equal to 0 and less
+     * than 'n' on each call. It should be called maximum 'n' times.
+     * Returns: a random integer
+     */
+    int next()
+    {
+        if (counter_ == size_) {
+            return -1;
+        }
+        else {
+            return vals_[counter_++];
+        }
+    }
+};
+
+}
+
+#endif //OPENCV_FLANN_RANDOM_H