Ejemplo n.º 1
0
Neighbors find_neighbors_bruteforce_impl(const RandomAccessIterator& begin, const RandomAccessIterator& end, 
                                         Callback callback, IndexType k)
{
	timed_context context("Distance sorting based neighbors search");
	typedef std::pair<RandomAccessIterator, ScalarType> DistanceRecord;
	typedef std::vector<DistanceRecord> Distances;

	Neighbors neighbors;
	neighbors.reserve(end-begin);
	for (RandomAccessIterator iter=begin; iter!=end; ++iter)
	{
		Distances distances;
		for (RandomAccessIterator around_iter=begin; around_iter!=end; ++around_iter)
			distances.push_back(std::make_pair(around_iter, callback.distance(iter,around_iter)));

		std::nth_element(distances.begin(),distances.begin()+k+1,distances.end(),
		                 distances_comparator<DistanceRecord>());

		LocalNeighbors local_neighbors;
		local_neighbors.reserve(k);
		for (typename Distances::const_iterator neighbors_iter=distances.begin(); 
				neighbors_iter!=distances.begin()+k+1; ++neighbors_iter)
		{
			if (neighbors_iter->first != iter) 
				local_neighbors.push_back(neighbors_iter->first - begin);
		}
		neighbors.push_back(local_neighbors);
	}
	return neighbors;
}
Ejemplo n.º 2
0
Neighbors find_neighbors_vptree_impl(const RandomAccessIterator& begin, const RandomAccessIterator& end, 
                                     Callback callback, IndexType k)
{
	timed_context context("VP-Tree based neighbors search");

	Neighbors neighbors;
	neighbors.reserve(end-begin);

	VantagePointTree<RandomAccessIterator,Callback> tree(begin,end,callback);

	for (RandomAccessIterator i=begin; i!=end; ++i)
	{
		LocalNeighbors local_neighbors = tree.search(i,k+1);
		std::remove(local_neighbors.begin(),local_neighbors.end(),i-begin);
		neighbors.push_back(local_neighbors);
	}

	return neighbors;
}