CombinedKernel.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 _COMBINEDKERNEL_H___
#define _COMBINEDKERNEL_H___

#include <shogun/lib/List.h>
#include <shogun/lib/DynamicObjectArray.h>
#include <shogun/io/SGIO.h>
#include <shogun/kernel/Kernel.h>

#include <shogun/features/Features.h>
#include <shogun/features/CombinedFeatures.h>

namespace shogun
{
class CFeatures;
class CCombinedFeatures;
class CList;
class CListElement;
class CCombinedKernel : public CKernel
{
    public:
        CCombinedKernel(int32_t size=10, bool append_subkernel_weights=false);

        virtual ~CCombinedKernel();

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

        virtual void cleanup();

        virtual EKernelType get_kernel_type()
        {
            return K_COMBINED;
        }

        virtual EFeatureType get_feature_type()
        {
            return F_UNKNOWN;
        }

        virtual EFeatureClass get_feature_class()
        {
            return C_COMBINED;
        }

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

        void list_kernels();

        inline CKernel* get_first_kernel()
        {
            return get_kernel(0);
        }

        inline CKernel* get_kernel(int32_t idx)
        {
            return (CKernel*) kernel_array->get_element(idx);
        }

        inline CKernel* get_last_kernel()
        {
            return get_kernel(get_num_kernels()-1);
        }

        inline bool insert_kernel(CKernel* k, int32_t idx)
        {
            ASSERT(k)
            adjust_num_lhs_rhs_initialized(k);

            if (!(k->has_property(KP_LINADD)))
                unset_property(KP_LINADD);

            return kernel_array->insert_element(k, idx);
        }

        inline bool append_kernel(CKernel* k)
        {
            ASSERT(k)
            adjust_num_lhs_rhs_initialized(k);

            if (!(k->has_property(KP_LINADD)))
                unset_property(KP_LINADD);

            int n = get_num_kernels();
            kernel_array->push_back(k);
            return n+1==get_num_kernels();
        }


        inline bool delete_kernel(int32_t idx)
        {
            bool succesful_deletion = kernel_array->delete_element(idx);

            if (get_num_kernels()==0)
            {
                num_lhs=0;
                num_rhs=0;
            }

            return succesful_deletion;
        }

        inline bool get_append_subkernel_weights()
        {
            return append_subkernel_weights;
        }

        inline int32_t get_num_subkernels()
        {
            if (append_subkernel_weights)
            {
                int32_t num_subkernels = 0;

                for (index_t k_idx=0; k_idx<get_num_kernels(); k_idx++)
                {
                    CKernel* k = get_kernel(k_idx);
                    num_subkernels += k->get_num_subkernels();
                    SG_UNREF(k);
                }
                return num_subkernels;
            }
            else
                return get_num_kernels();
        }

        int32_t get_num_kernels()
        {
            return kernel_array->get_num_elements();
        }

        virtual bool has_features()
        {
            return initialized;
        }

        virtual void remove_lhs();

        virtual void remove_rhs();

        virtual void remove_lhs_and_rhs();

        virtual bool init_optimization(
            int32_t count, int32_t *IDX, float64_t * weights);

        virtual bool delete_optimization();

        virtual float64_t compute_optimized(int32_t idx);

        virtual void compute_batch(
            int32_t num_vec, int32_t* vec_idx, float64_t* target,
            int32_t num_suppvec, int32_t* IDX, float64_t* alphas,
            float64_t factor=1.0);

        static void* compute_optimized_kernel_helper(void* p);

        static void* compute_kernel_helper(void* p);

        void emulate_compute_batch(
            CKernel* k, int32_t num_vec, int32_t* vec_idx, float64_t* target,
            int32_t num_suppvec, int32_t* IDX, float64_t* weights);

        virtual void add_to_normal(int32_t idx, float64_t weight);

        virtual void clear_normal();

        virtual void compute_by_subkernel(
            int32_t idx, float64_t * subkernel_contrib);

        virtual const float64_t* get_subkernel_weights(int32_t& num_weights);

        virtual SGVector<float64_t> get_subkernel_weights();

        virtual void set_subkernel_weights(SGVector<float64_t> weights);

        virtual void set_optimization_type(EOptimizationType t);

        bool precompute_subkernels();

        static CCombinedKernel* obtain_from_generic(CKernel* kernel);

        SGMatrix<float64_t> get_parameter_gradient(const TParameter* param,
                index_t index=-1);

        inline CDynamicObjectArray* get_array()
        {
            SG_REF(kernel_array);
            return kernel_array;
        }

        static CList* combine_kernels(CList* kernel_list);

    protected:
        virtual float64_t compute(int32_t x, int32_t y);

        inline void adjust_num_lhs_rhs_initialized(CKernel* k)
        {
            ASSERT(k)

            if (k->get_num_vec_lhs())
            {
                if (num_lhs)
                    ASSERT(num_lhs==k->get_num_vec_lhs())
                num_lhs=k->get_num_vec_lhs();

                if (!get_num_subkernels())
                {
                    initialized=true;
#ifdef USE_SVMLIGHT
                    cache_reset();
#endif //USE_SVMLIGHT
                }
            }
            else
                initialized=false;

            if (k->get_num_vec_rhs())
            {
                if (num_rhs)
                    ASSERT(num_rhs==k->get_num_vec_rhs())
                num_rhs=k->get_num_vec_rhs();

                if (!get_num_subkernels())
                {
                    initialized=true;
#ifdef USE_SVMLIGHT
                    cache_reset();
#endif //USE_SVMLIGHT
                }
            }
            else
                initialized=false;
        }

    private:
        void init();

    protected:
        CDynamicObjectArray* kernel_array;
        int32_t   sv_count;
        int32_t*  sv_idx;
        float64_t* sv_weight;
        float64_t* subkernel_weights_buffer;
        bool append_subkernel_weights;
        bool initialized;
};
}
#endif /* _COMBINEDKERNEL_H__ */