ImplicitWeightedSpecFeatures.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) 2009-2010 Soeren Sonnenburg
00008  * Copyright (C) 2009 Fraunhofer Institute FIRST and Max-Planck-Society
00009  * Copyright (C) 2010 Berlin Institute of Technology
00010  */
00011 
00012 #ifndef _IMPLICITSPECFEATURES_H___
00013 #define _IMPLICITSPECFEATURES_H___
00014 
00015 #include "lib/common.h"
00016 #include "lib/io.h"
00017 #include "features/DotFeatures.h"
00018 #include "features/StringFeatures.h"
00019 
00020 namespace shogun
00021 {
00022 
00023 template <class ST> class CStringFeatures;
00024 
00030 class CImplicitWeightedSpecFeatures : public CDotFeatures
00031 {
00032     public:
00033 
00039         CImplicitWeightedSpecFeatures(CStringFeatures<uint16_t>* str, bool normalize=true);
00040 
00042         CImplicitWeightedSpecFeatures(const CImplicitWeightedSpecFeatures & orig);
00043 
00044         virtual ~CImplicitWeightedSpecFeatures();
00045 
00050         virtual CFeatures* duplicate() const;
00051 
00059         inline virtual int32_t get_dim_feature_space()
00060         {
00061             return spec_size;
00062         }
00063 
00070         virtual float64_t dot(int32_t vec_idx1, int32_t vec_idx2);
00071 
00078         virtual float64_t dense_dot(int32_t vec_idx1, const float64_t* vec2, int32_t vec2_len);
00079 
00088         virtual void add_to_dense_vec(float64_t alpha, int32_t vec_idx1, float64_t* vec2, int32_t vec2_len, bool abs_val=false);
00089 
00095         virtual inline int32_t get_nnz_features_for_vector(int32_t num)
00096         {
00097             int32_t vlen=-1;
00098             bool free_vec;
00099             uint16_t* vec1=strings->get_feature_vector(num, vlen, free_vec);
00100             strings->free_feature_vector(vec1, num, free_vec);
00101             int32_t nnz=0;
00102             for (int32_t i=1; i<=degree; i++)
00103                 nnz+=CMath::min(CMath::pow(alphabet_size,i), vlen);
00104             return nnz;
00105         }
00106 
00111         inline virtual EFeatureType get_feature_type()
00112         {
00113             return F_UNKNOWN;
00114         }
00115 
00120         inline virtual EFeatureClass get_feature_class()
00121         {
00122             return C_WEIGHTEDSPEC;
00123         }
00124 
00129         inline virtual int32_t get_num_vectors()
00130         {
00131             return num_strings;
00132         }
00133 
00138         inline virtual int32_t get_size()
00139         {
00140             return sizeof(float64_t);
00141         }
00142 
00147         bool set_wd_weights();
00148 
00155         bool set_weights(float64_t* w, int32_t d);
00156 
00158         struct wspec_feature_iterator
00159         {
00161             uint16_t* vec;
00163             int32_t vidx;
00165             int32_t vlen;
00167             bool vfree;
00168 
00173             int32_t offs;
00174             int32_t d;
00175             int32_t j;
00176             uint8_t mask;
00177             float64_t alpha;
00179         };
00180 
00190         virtual void* get_feature_iterator(int32_t vector_index);
00191 
00202         virtual bool get_next_feature(int32_t& index, float64_t& value, void* iterator);
00203 
00209         virtual void free_feature_iterator(void* iterator);
00210 
00212         inline virtual const char* get_name() const { return "ImplicitWeightedSpecFeatures"; }
00213 
00214     protected:
00219         void compute_normalization_const();
00220 
00221     protected:
00223         CStringFeatures<uint16_t>* strings;
00224 
00226         float64_t* normalization_factors;
00228         int32_t num_strings;
00230         int32_t alphabet_size;
00231 
00233         int32_t degree;
00235         int32_t spec_size;
00236 
00238         float64_t* spec_weights;
00239 };
00240 }
00241 #endif // _IMPLICITSPECFEATURES_H___
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