HashedWDFeatures.h

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00001 /*
00002  * This program is free software; you can redistribute it and/or modify
00003  * it under the terms of the GNU General Public License as published by
00004  * the Free Software Foundation; either version 3 of the License, or
00005  * (at your option) any later version.
00006  *
00007  * Written (W) 2010 Soeren Sonnenburg
00008  * Copyright (C) 2010 Berlin Institute of Technology
00009  */
00010 
00011 #ifndef _HASHEDWDFEATURES_H___
00012 #define _HASHEDWDFEATURES_H___
00013 
00014 #include "lib/common.h"
00015 #include "features/DotFeatures.h"
00016 #include "features/StringFeatures.h"
00017 #include "lib/Hash.h"
00018 
00019 namespace shogun
00020 {
00021 template <class ST> class CStringFeatures;
00022 
00028 class CHashedWDFeatures : public CDotFeatures
00029 {
00030     public:
00031 
00040         CHashedWDFeatures(CStringFeatures<uint8_t>* str, int32_t start_order,
00041                 int32_t order,  int32_t from_order, int32_t hash_bits=12);
00042 
00044         CHashedWDFeatures(const CHashedWDFeatures & orig);
00045 
00047         virtual ~CHashedWDFeatures();
00048 
00056         inline virtual int32_t get_dim_feature_space()
00057         {
00058             return w_dim;
00059         }
00060 
00067         virtual float64_t dot(int32_t vec_idx1, int32_t vec_idx2);
00068 
00075         virtual float64_t dense_dot(int32_t vec_idx1, const float64_t* vec2, int32_t vec2_len);
00076 
00085         virtual void add_to_dense_vec(float64_t alpha, int32_t vec_idx1, float64_t* vec2, int32_t vec2_len, bool abs_val=false);
00086 
00092         virtual inline int32_t get_nnz_features_for_vector(int32_t num)
00093         {
00094             int32_t vlen=-1;
00095             bool free_vec;
00096             uint8_t* vec=strings->get_feature_vector(num, vlen, free_vec);
00097             strings->free_feature_vector(vec, num, free_vec);
00098             return degree*vlen;
00099         }
00100 
00102         struct hashed_wd_feature_iterator
00103         {
00105             uint16_t* vec;
00107             int32_t vidx;
00109             int32_t vlen;
00111             bool vfree;
00112 
00114             int32_t index;
00115 
00116         };
00117 
00127         virtual void* get_feature_iterator(int32_t vector_index)
00128         {
00129             SG_NOTIMPLEMENTED;
00130             return NULL;
00131         }
00132 
00143         virtual bool get_next_feature(int32_t& index, float64_t& value, void* iterator)
00144         {
00145             SG_NOTIMPLEMENTED;
00146             return NULL;
00147         }
00148 
00154         virtual void free_feature_iterator(void* iterator)
00155         {
00156             SG_NOTIMPLEMENTED;
00157         }
00158 
00163         virtual CFeatures* duplicate() const;
00164 
00169         inline virtual EFeatureType get_feature_type()
00170         {
00171             return F_UNKNOWN;
00172         }
00173 
00178         inline virtual EFeatureClass get_feature_class()
00179         {
00180             return C_WD;
00181         }
00182 
00183         inline virtual int32_t get_num_vectors()
00184         {
00185             return num_strings;
00186         }
00187 
00188         inline virtual int32_t get_size()
00189         {
00190             return sizeof(float64_t);
00191         }
00192 
00195         void set_normalization_const(float64_t n=0);
00196 
00198         inline float64_t get_normalization_const()
00199         {
00200             return normalization_const;
00201         }
00202 
00204         inline virtual const char* get_name() const { return "HashedWDFeatures"; }
00205 
00206     protected:
00207 
00209         void set_wd_weights();
00210 
00211     protected:
00213         CStringFeatures<uint8_t>* strings;
00214 
00216         int32_t degree;
00218         int32_t start_degree;
00220         int32_t from_degree;
00222         int32_t string_length;
00224         int32_t num_strings;
00226         int32_t alphabet_size;
00228         int32_t w_dim;
00230         int32_t partial_w_dim;
00232         float64_t* wd_weights;
00234         uint32_t mask;
00236         int32_t m_hash_bits;
00237 
00239         float64_t normalization_const;
00240 };
00241 }
00242 #endif // _HASHEDWDFEATURES_H___
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