MultidimensionalScaling.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) 2011 Sergey Lisitsyn
 * Copyright (C) 2011 Berlin Institute of Technology and Max-Planck-Society
 */

#ifndef MULTIDIMENSIONALSCALING_H_
#define MULTIDIMENSIONALSCALING_H_
#include <shogun/lib/config.h>
#ifdef HAVE_LAPACK
#include <shogun/preprocessor/DimensionReductionPreprocessor.h>
#include <shogun/features/Features.h>
#include <shogun/distance/Distance.h>

namespace shogun
{

class CFeatures;

class CDistance;

class CMultidimensionalScaling: public CDimensionReductionPreprocessor
{
public:

    /* constructor */
    CMultidimensionalScaling();

    /* destructor */
    virtual ~CMultidimensionalScaling();

    virtual bool init(CFeatures* features);

    virtual void cleanup();

    virtual CSimpleFeatures<float64_t>* apply_to_distance(CDistance* distance);

    virtual SGMatrix<float64_t> apply_to_feature_matrix(CFeatures* features);

    virtual SGVector<float64_t> apply_to_feature_vector(SGVector<float64_t> vector);

    virtual inline const char* get_name() const { return "MultidimensionalScaling"; };

    virtual inline EPreprocessorType get_type() const { return P_MULTIDIMENSIONALSCALING; };

    SGVector<float64_t> get_eigenvalues() const
    {
        return m_eigenvalues;
    }

    void set_landmark_number(int32_t num)
    {
        if (num<3)
            SG_ERROR("Landmark number should be greater than 3 (%d given).", num);
        m_landmark_number = num;
    };
    
    int32_t get_landmark_number() const
    {
        return m_landmark_number;
    };

    void set_landmark(bool landmark)
    {
        m_landmark = landmark;
    };

    bool get_landmark() const
    {
        return m_landmark;
    };

protected:

    void init();

    SGMatrix<float64_t> classic_embedding(SGMatrix<float64_t> distance_matrix);

    SGMatrix<float64_t> landmark_embedding(SGMatrix<float64_t> distance_matrix);

protected:

    static void* run_triangulation_thread(void* p);

    static SGVector<int32_t> shuffle(int32_t count, int32_t total_count);

protected:

    SGVector<float64_t> m_eigenvalues;

    bool m_landmark;

    int32_t m_landmark_number;

};

}
#endif /* HAVE_LAPACK */
#endif /* MULTIDIMENSIONALSCALING_H_ */