DotKernel.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) 2009 Soeren Sonnenburg
 * Copyright (C) 2010 Berlin Institute of Technology
 */

#ifndef _DOTKERNEL_H___
#define _DOTKERNEL_H___

#include <shogun/kernel/Kernel.h>
#include <shogun/features/DotFeatures.h>
#include <shogun/io/SGIO.h>

namespace shogun
{
class CDotKernel : public CKernel
{
    public:
        CDotKernel() : CKernel() {}

        CDotKernel(int32_t cachesize) : CKernel(cachesize) {}

        CDotKernel(CFeatures* l, CFeatures* r) : CKernel(10)
        {
            init(l, r);
        }

        virtual bool init(CFeatures* l, CFeatures* r)
        {
            CKernel::init(l,r);

            ASSERT(l->has_property(FP_DOT))
            ASSERT(r->has_property(FP_DOT))
            ASSERT(l->get_feature_type() == r->get_feature_type())
            ASSERT(l->get_feature_class() == r->get_feature_class())

            if ( ((CDotFeatures*) l)->get_dim_feature_space() != ((CDotFeatures*) r)->get_dim_feature_space() )
            {
                SG_ERROR("train or test features #dimension mismatch (l:%d vs. r:%d)\n",
                        ((CDotFeatures*) l)->get_dim_feature_space(),((CDotFeatures*) r)->get_dim_feature_space());
            }
            return true;
        }

        virtual EFeatureClass get_feature_class() { return C_ANY; }

        virtual EFeatureType get_feature_type() { return F_ANY; }

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

        virtual EKernelType get_kernel_type()=0 ;

    protected:
        virtual float64_t compute(int32_t idx_a, int32_t idx_b)
        {
            return ((CDotFeatures*) lhs)->dot(idx_a, ((CDotFeatures*) rhs), idx_b);
        }
};
}
#endif /* _DOTKERNEL_H__ */