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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___