HomogeneousKernelMap.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) 2012 Viktor Gal
 * Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
 */

#ifndef _CHOMOGENEOUKERNELMAP__H__
#define _CHOMOGENEOUKERNELMAP__H__

#include <shogun/preprocessor/DensePreprocessor.h>
#include <shogun/features/Features.h>
#include <shogun/lib/common.h>

#include <stdio.h>

namespace shogun
{
    enum HomogeneousKernelType {
      HomogeneousKernelIntersection = 0, 
      HomogeneousKernelChi2, 
      HomogeneousKernelJS 
    };

    enum HomogeneousKernelMapWindowType {
      HomogeneousKernelMapWindowUniform = 0, 
      HomogeneousKernelMapWindowRectangular = 1, 
    };

    class CHomogeneousKernelMap : public CDensePreprocessor<float64_t>
    {
        public:
            CHomogeneousKernelMap();

            CHomogeneousKernelMap(HomogeneousKernelType kernel, HomogeneousKernelMapWindowType wType,
                                  float64_t gamma = 1.0, uint64_t order = 1, float64_t period = -1);

            virtual ~CHomogeneousKernelMap();

            virtual bool init(CFeatures* features);

            virtual void cleanup();

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

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

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

            virtual EPreprocessorType get_type() const { return P_HOMOGENEOUSKERNELMAP; }

            void set_kernel_type(HomogeneousKernelType k);
            HomogeneousKernelType get_kernel_type() const;

            void set_window_type(HomogeneousKernelMapWindowType w);
            HomogeneousKernelMapWindowType get_window_type() const;

            void set_gamma(float64_t g);
            float64_t get_gamma(float64_t g) const;

            void set_order(uint64_t o);
            uint64_t get_order() const;

            void set_period(float64_t p);
            float64_t get_period() const;

        private:
            void init ();
            void register_params ();
            inline float64_t get_smooth_spectrum (float64_t omega) const;
            inline float64_t sinc (float64_t x) const;
            inline float64_t get_spectrum (float64_t omega) const;
            SGVector<float64_t> apply_to_vector(const SGVector<float64_t>& in_v) const;

        private:
            HomogeneousKernelType m_kernel;
            HomogeneousKernelMapWindowType m_window;
            float64_t m_gamma;
            float64_t m_period;
            uint64_t m_numSubdivisions;
            float64_t m_subdivision;
            uint64_t m_order;
            int64_t m_minExponent;
            int64_t m_maxExponent;
            SGVector<float64_t> m_table;
    };
}
#endif /* _CHOMOGENEOUKERNELMAP__H__ */