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