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 *
 * 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.
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 * THE BSD LICENSE
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#ifndef LINEARSEARCH_H
#define LINEARSEARCH_H

#include "flann/general.h"
#include "flann/algorithms/nn_index.h"

namespace flann
{

struct LinearIndexParams : public IndexParams {
	LinearIndexParams() : IndexParams(FLANN_INDEX_LINEAR) {};

	void fromParameters(const FLANNParameters& p)
	{
		assert(p.algorithm==algorithm);
	}

	void toParameters(FLANNParameters& p) const
	{
		p.algorithm = algorithm;
	}

	void print() const
	{
		logger.info("Index type: %d\n",(int)algorithm);
	}
};

template <typename Distance>
class LinearIndex : public NNIndex<Distance>
{
	typedef typename Distance::ElementType ElementType;
	typedef typename Distance::ResultType DistanceType;

	const Matrix<ElementType> dataset;
	const LinearIndexParams index_params;

	Distance distance;

public:

	LinearIndex(const Matrix<ElementType>& inputData, const LinearIndexParams& params = LinearIndexParams(),
			Distance d = Distance()) :
		dataset(inputData), index_params(params), distance(d)
	{
	}

    flann_algorithm_t getType() const
    {
        return FLANN_INDEX_LINEAR;
    }


	size_t size() const
	{
		return dataset.rows;
	}

	size_t veclen() const
	{
		return dataset.cols;
	}


	int usedMemory() const
	{
		return 0;
	}

	void buildIndex()
	{
		/* nothing to do here for linear search */
	}

    void saveIndex(FILE* stream)
    {
		/* nothing to do here for linear search */
    }


    void loadIndex(FILE* stream)
    {
		/* nothing to do here for linear search */
    }

	void findNeighbors(ResultSet<DistanceType>& resultSet, const ElementType* vec, const SearchParams& searchParams)
	{
		for (size_t i=0;i<dataset.rows;++i) {
			DistanceType dist = distance(dataset[i],vec, dataset.cols);
			resultSet.addPoint(dist,i);
		}
	}

	const IndexParams* getParameters() const
	{
		return &index_params;
	}

};

}

#endif // LINEARSEARCH_H
