HashedDocDotFeatures.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) 2013 Evangelos Anagnostopoulos
 * Copyright (C) 2013 Evangelos Anagnostopoulos
 */

#ifndef _HASHEDDOCDOTFEATURES__H__
#define _HASHEDDOCDOTFEATURES__H__

#include <shogun/lib/config.h>

#include <shogun/features/DotFeatures.h>
#include <shogun/features/StringFeatures.h>
#include <shogun/converter/HashedDocConverter.h>
#include <shogun/lib/Tokenizer.h>

namespace shogun {
template<class ST> class CStringFeatures;
template<class ST> class SGMatrix;
class CDotFeatures;
class CHashedDocConverter;
class CTokenizer;

class CHashedDocDotFeatures: public CDotFeatures
{
public:

    CHashedDocDotFeatures(int32_t hash_bits=0, CStringFeatures<char>* docs=NULL,
            CTokenizer* tzer=NULL, bool normalize=true, int32_t n_grams=1, int32_t skips=0, int32_t size=0);

    CHashedDocDotFeatures(const CHashedDocDotFeatures& orig);

    CHashedDocDotFeatures(CFile* loader);

    virtual ~CHashedDocDotFeatures();

    virtual int32_t get_dim_feature_space() const;

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

    virtual float64_t dense_dot_sgvec(int32_t vec_idx1, const SGVector<float64_t> vec2);

    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);

    virtual int32_t get_nnz_features_for_vector(int32_t num);

    virtual void* get_feature_iterator(int32_t vector_index);

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

    virtual void free_feature_iterator(void* iterator);

    void set_doc_collection(CStringFeatures<char>* docs);

    virtual const char* get_name() const;

    virtual CFeatures* duplicate() const;

    virtual EFeatureType get_feature_type() const;

    virtual EFeatureClass get_feature_class() const;

    virtual int32_t get_num_vectors() const;

    static uint32_t calculate_token_hash(char* token, int32_t length,
            int32_t num_bits, uint32_t seed);

private:
    void init(int32_t hash_bits, CStringFeatures<char>* docs, CTokenizer* tzer,
        bool normalize, int32_t n_grams, int32_t skips);

protected:
    CStringFeatures<char>* doc_collection;

    int32_t num_bits;

    CTokenizer* tokenizer;

    bool should_normalize;

    int32_t ngrams;

    int32_t tokens_to_skip;
};
}

#endif