SparsePolyFeatures.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) 2010 Soeren Sonnenburg
 * Copyright (C) 2010 Berlin Institute of Technology
 */
#ifndef _SPARSEPOLYFEATURES__H__
#define _SPARSEPOLYFEATURES__H__

#include <shogun/lib/config.h>

#include <shogun/lib/common.h>
#include <shogun/features/DotFeatures.h>
#include <shogun/features/SparseFeatures.h>

namespace shogun
{
class CSparsePolyFeatures : public CDotFeatures
{
    public:
        CSparsePolyFeatures();

        CSparsePolyFeatures(CSparseFeatures<float64_t>* feat, int32_t degree, bool normalize, int32_t hash_bits);

        virtual ~CSparsePolyFeatures();

        CSparsePolyFeatures(const CSparsePolyFeatures & orig);

        virtual int32_t get_dim_feature_space() const;

        virtual int32_t get_nnz_features_for_vector(int32_t num);

        virtual EFeatureType get_feature_type() const;

        virtual EFeatureClass get_feature_class() const;

        virtual int32_t get_num_vectors() const;

        virtual float64_t dot(int32_t vec_idx1, CDotFeatures* df, int32_t vec_idx2);

        #ifndef DOXYGEN_SHOULD_SKIP_THIS

        struct sparse_poly_feature_iterator
        {
            uint16_t* vec;
            int32_t vidx;
            int32_t vlen;
            bool vfree;

            int32_t index;
        };
        #endif

        virtual void* get_feature_iterator(int32_t vector_index);

        bool get_next_feature(int32_t& index, float64_t& value, void* iterator);

        void free_feature_iterator(void* iterator);

        CFeatures* duplicate() const;

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

        virtual float64_t dense_dot(int32_t vec_idx1, const float64_t* vec2, int32_t vec2_len);

        virtual void add_to_dense_vec(float64_t alpha, int32_t vec_idx1, float64_t* vec2, int32_t vec2_len, bool abs_val=false);

    protected:
        void store_normalization_values();

    protected:
        CSparseFeatures<float64_t>* m_feat;
        int32_t m_degree;
        bool m_normalize;
        int32_t m_input_dimensions;
        int32_t m_output_dimensions;
        float64_t* m_normalization_values;
        uint32_t mask;
        int32_t m_hash_bits;
    private:
        void init();

    private:
        int32_t m_normalization_values_len;
};
}
#endif // _SPARSEPOLYFEATURES__H__