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CustomMahalanobisDistance.h
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CustomMahalanobisDistance.h
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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* Written (W) 2013 Fernando J. Iglesias Garcia
* Copyright (C) 2013 Fernando J. Iglesias Garcia
*/
#ifndef CUSTOM_MAHALANOBIS_DISTANCE_
#define CUSTOM_MAHALANOBIS_DISTANCE_
#ifdef HAVE_EIGEN3
#include <shogun/lib/config.h>
#include <shogun/distance/RealDistance.h>
#include <shogun/features/DenseFeatures.h>
#include <shogun/lib/SGMatrix.h>
namespace shogun
{
/**
* @brief Class CustomMahalanobisDistance used to compute the distance between feature
* vectors \f$ \vec{x_i} \f$ and \f$ \vec{x_j} \f$ as \f$ (\vec{x_i} - \vec{x_j})^T \mathbf{M}
* (\vec{x_i} - \vec{x_j}) \f$, given the matrix \f$ \mathbf{M} \f$ which will be referred to as
* Mahalanobis matrix.
*
*/
class CCustomMahalanobisDistance : public CRealDistance
{
public:
/** default constructor */
CCustomMahalanobisDistance();
/** standard constructor
*
* @param l features of left hand side
* @param r features of right hand side
* @param m Mahalanobis matrix used to compute distances
*/
CCustomMahalanobisDistance(CFeatures* l, CFeatures* r, SGMatrix<float64_t> m);
/** destructor */
virtual ~CCustomMahalanobisDistance();
/** cleanup distance, here only because it is abstract in CDistance. It does nothing */
virtual void cleanup();
/** @return name of SGSerializable */
virtual const char* get_name() const;
/** get distance type
*
* @return distance type CUSTOMMAHALANOBIS
*/
virtual EDistanceType get_distance_type();
protected:
/**
* compute distance between feature idx_a in lhs features and feature idx_b
* in rhs features
*
* @param idx_a feature vector in lhs at idx_a
* @param idx_b feature vector in rhs at idx_b
*
* @return distance value
*/
virtual float64_t compute(int32_t idx_a, int32_t idx_b);
private:
/** register parameters */
void register_params();
private:
/** Mahalanobis matrix used to compute distances */
SGMatrix<float64_t> m_mahalanobis_matrix;
}; /* class CCustomMahalanobisDistance */
} /* namespace shogun */
#endif /* HAVE_EIGEN3 */
#endif /* CUSTOM_MAHALANOBIS_DISTANCE_ */