SimpleLocalityImprovedStringKernel.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) 1999-2008 Gunnar Raetsch
 * Written (W) 2013 Soeren Sonnenburg
 * Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society
 * Copyright (C) 2013 Soeren Sonnenburg
 */

#ifndef _SIMPLELOCALITYIMPROVEDSTRINGKERNEL_H___
#define _SIMPLELOCALITYIMPROVEDSTRINGKERNEL_H___

#include <shogun/lib/common.h>
#include <shogun/kernel/string/StringKernel.h>

namespace shogun
{
class CSimpleLocalityImprovedStringKernel: public CStringKernel<char>
{
    public:
        CSimpleLocalityImprovedStringKernel();

        CSimpleLocalityImprovedStringKernel(int32_t size, int32_t length,
            int32_t inner_degree, int32_t outer_degree);

        CSimpleLocalityImprovedStringKernel(
            CStringFeatures<char>* l, CStringFeatures<char>* r,
            int32_t length, int32_t inner_degree, int32_t outer_degree);

        virtual ~CSimpleLocalityImprovedStringKernel();

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

        virtual void cleanup();

        virtual EKernelType get_kernel_type()
        {
            return K_SIMPLELOCALITYIMPROVED;
        }

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

    private:
        float64_t dot_pyr (const char* const x1, const char* const x2,
                const int32_t NOF_NTS, const int32_t NTWIDTH,
                const int32_t DEGREE1, const int32_t DEGREE2, float64_t *pyra);

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

    private:
        void init();

    protected:
        int32_t length;
        int32_t inner_degree;
        int32_t outer_degree;

        SGVector<float64_t> pyramid_weights;
};
}
#endif /* _SIMPLELOCALITYIMPROVEDSTRINGKERNEL_H___ */