Distance.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) 2006-2009 Christian Gehl
 * Written (W) 2006-2009 Soeren Sonnenburg
 * Copyright (C) 2006-2009 Fraunhofer Institute FIRST and Max-Planck-Society
 */

#ifndef _DISTANCE_H___
#define _DISTANCE_H___

#include <shogun/lib/config.h>

#include <shogun/lib/common.h>
#include <shogun/io/File.h>
#include <shogun/mathematics/Math.h>
#include <shogun/base/SGObject.h>
#include <shogun/features/FeatureTypes.h>
#include <shogun/features/Features.h>
#include <shogun/lib/SGMatrix.h>

namespace shogun
{
class CFile;
class CMath;
class CFeatures;

enum EDistanceType
{
    D_UNKNOWN = 0,
    D_MINKOWSKI = 10,
    D_MANHATTAN = 20,
    D_CANBERRA = 30,
    D_CHEBYSHEW = 40,
    D_GEODESIC = 50,
    D_JENSEN = 60,
    D_MANHATTANWORD = 70,
    D_HAMMINGWORD = 80 ,
    D_CANBERRAWORD = 90,
    D_SPARSEEUCLIDEAN = 100,
    D_EUCLIDEAN = 110,
    D_CHISQUARE = 120,
    D_TANIMOTO = 130,
    D_COSINE = 140,
    D_BRAYCURTIS = 150,
    D_CUSTOM = 160,
    D_ATTENUATEDEUCLIDEAN = 170,
    D_MAHALANOBIS = 180,
    D_DIRECTOR = 190,
    D_CUSTOMMAHALANOBIS = 200
};


class CDistance : public CSGObject
{
    public:
        CDistance();

        CDistance(CFeatures* lhs, CFeatures* rhs);
        virtual ~CDistance();

        virtual float64_t distance(int32_t idx_a, int32_t idx_b);

        virtual float64_t distance_upper_bounded(int32_t idx_a, int32_t idx_b, float64_t upper_bound)
        {
            return distance(idx_a, idx_b);
        }

        SGMatrix<float64_t> get_distance_matrix()
        {
            return get_distance_matrix<float64_t>();
        }

        template <class T> SGMatrix<T> get_distance_matrix();

        int32_t compute_row_start(int64_t offs, int32_t n, bool symmetric)
        {
            int32_t i_start;

            if (symmetric)
                i_start=(int32_t) CMath::floor(n-CMath::sqrt(CMath::sq((float64_t) n)-offs));
            else
                i_start=(int32_t) (offs/int64_t(n));

            return i_start;
        }

        template <class T> static void* get_distance_matrix_helper(void* p);

        virtual bool init(CFeatures* lhs, CFeatures* rhs);

        virtual void cleanup()=0;

        void load(CFile* loader);

        void save(CFile* writer);

        inline CFeatures* get_lhs() { SG_REF(lhs); return lhs; };

        inline CFeatures* get_rhs() { SG_REF(rhs); return rhs; };

        CFeatures* replace_rhs(CFeatures* rhs);

        CFeatures* replace_lhs(CFeatures* lhs);

        virtual void remove_lhs_and_rhs();

        virtual void remove_lhs();

        virtual void remove_rhs();

        virtual EDistanceType get_distance_type()=0 ;

        virtual EFeatureType get_feature_type()=0;

        virtual EFeatureClass get_feature_class()=0;

        inline bool get_precompute_matrix() { return precompute_matrix ;  }

        virtual void set_precompute_matrix(bool flag)
        {
            precompute_matrix=flag;

            if (!precompute_matrix)
            {
                SG_FREE(precomputed_matrix);
                precomputed_matrix=NULL;
            }
        }

        virtual int32_t get_num_vec_lhs()
        {
            return num_lhs;
        }

        virtual int32_t get_num_vec_rhs()
        {
            return num_rhs;
        }

        virtual bool has_features()
        {
            return lhs && rhs;
        }

        inline bool lhs_equals_rhs()
        {
            return lhs==rhs;
        }

    protected:

        static void* run_distance_thread(void* p);

        virtual float64_t compute(int32_t idx_a, int32_t idx_b)=0;

        void do_precompute_matrix();

    private:
        void init();

    protected:
        float32_t * precomputed_matrix;

        bool precompute_matrix;

        CFeatures* lhs;
        CFeatures* rhs;

        int32_t num_lhs;
        int32_t num_rhs;

};
} // namespace shogun
#endif