HistogramWordStringKernel.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) 1999-2009 Soeren Sonnenburg
 * Written (W) 1999-2008 Gunnar Raetsch
 * Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society
 */

#ifndef _HISTOGRAMWORDKERNEL_H___
#define _HISTOGRAMWORDKERNEL_H___

#include <shogun/lib/common.h>
#include <shogun/kernel/string/StringKernel.h>
#include <shogun/classifier/PluginEstimate.h>
#include <shogun/features/StringFeatures.h>

namespace shogun
{
    class CPluginEstimate;
    template <class T> class CStringFeatures;
class CHistogramWordStringKernel: public CStringKernel<uint16_t>
{
    public:
        CHistogramWordStringKernel();

        CHistogramWordStringKernel(int32_t size, CPluginEstimate* pie);

        CHistogramWordStringKernel(
            CStringFeatures<uint16_t>* l, CStringFeatures<uint16_t>* r,
            CPluginEstimate* pie);

        virtual ~CHistogramWordStringKernel();

        virtual bool init(CFeatures* l, CFeatures* r);

        virtual void cleanup();

        virtual EKernelType get_kernel_type() { return K_HISTOGRAM; }

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

    protected:
        float64_t compute(int32_t idx_a, int32_t idx_b);

        inline int32_t compute_index(int32_t position, uint16_t symbol)
        {
            return position*num_symbols+symbol+1;
        }

    private:
        void init();

    protected:
        CPluginEstimate* estimate;

        float64_t* mean;
        float64_t* variance;

        float64_t* sqrtdiag_lhs;
        float64_t* sqrtdiag_rhs;

        float64_t* ld_mean_lhs;
        float64_t* ld_mean_rhs;

        float64_t* plo_lhs;
        float64_t* plo_rhs;

        int32_t num_params;
        int32_t num_params2;
        int32_t num_symbols;
        float64_t sum_m2_s2;

        bool initialized;
};
}
#endif /* _HISTOGRAMWORDKERNEL_H__ */