WeightedCommWordStringKernel.cpp

Go to the documentation of this file.
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) 1999-2008 Soeren Sonnenburg
00008  * Copyright (C) 1999-2008 Fraunhofer Institute FIRST and Max-Planck-Society
00009  */
00010 
00011 #include "lib/common.h"
00012 #include "kernel/WeightedCommWordStringKernel.h"
00013 #include "features/StringFeatures.h"
00014 #include "lib/io.h"
00015 
00016 CWeightedCommWordStringKernel::CWeightedCommWordStringKernel(
00017     int32_t size, bool us)
00018 : CCommWordStringKernel(size, us), degree(0), weights(NULL)
00019 {
00020     init_dictionary(1<<(sizeof(uint16_t)*9));
00021     ASSERT(us==false);
00022 }
00023 
00024 CWeightedCommWordStringKernel::CWeightedCommWordStringKernel(
00025     CStringFeatures<uint16_t>* l, CStringFeatures<uint16_t>* r, bool us,
00026     int32_t size)
00027 : CCommWordStringKernel(size, us), degree(0), weights(NULL)
00028 {
00029     init_dictionary(1<<(sizeof(uint16_t)*9));
00030     ASSERT(us==false);
00031 
00032     init(l,r);
00033 }
00034 
00035 CWeightedCommWordStringKernel::~CWeightedCommWordStringKernel()
00036 {
00037     delete[] weights;
00038 }
00039 
00040 bool CWeightedCommWordStringKernel::init(CFeatures* l, CFeatures* r)
00041 {
00042     ASSERT(((CStringFeatures<uint16_t>*) l)->get_order() ==
00043             ((CStringFeatures<uint16_t>*) r)->get_order());
00044     degree=((CStringFeatures<uint16_t>*) l)->get_order();
00045     set_wd_weights();
00046 
00047     CCommWordStringKernel::init(l,r);
00048     return init_normalizer();
00049 }
00050 
00051 void CWeightedCommWordStringKernel::cleanup()
00052 {
00053     delete[] weights;
00054     weights=NULL;
00055 
00056     CCommWordStringKernel::cleanup();
00057 }
00058 
00059 bool CWeightedCommWordStringKernel::set_wd_weights()
00060 {
00061     delete[] weights;
00062     weights=new float64_t[degree];
00063 
00064     int32_t i;
00065     float64_t sum=0;
00066     for (i=0; i<degree; i++)
00067     {
00068         weights[i]=degree-i;
00069         sum+=weights[i];
00070     }
00071     for (i=0; i<degree; i++)
00072         weights[i]/=sum;
00073 
00074     return weights!=NULL;
00075 }
00076 
00077 bool CWeightedCommWordStringKernel::set_weights(float64_t* w, int32_t d)
00078 {
00079     ASSERT(d==degree);
00080 
00081     delete[] weights;
00082     weights=new float64_t[degree];
00083     for (int32_t i=0; i<degree; i++)
00084         weights[i]=w[i];
00085     return true;
00086 }
00087   
00088 float64_t CWeightedCommWordStringKernel::compute_helper(
00089     int32_t idx_a, int32_t idx_b, bool do_sort)
00090 {
00091     int32_t alen, blen;
00092 
00093     CStringFeatures<uint16_t>* l = (CStringFeatures<uint16_t>*) lhs;
00094     CStringFeatures<uint16_t>* r = (CStringFeatures<uint16_t>*) rhs;
00095 
00096     uint16_t* av=l->get_feature_vector(idx_a, alen);
00097     uint16_t* bv=r->get_feature_vector(idx_b, blen);
00098 
00099     uint16_t* avec=av;
00100     uint16_t* bvec=bv;
00101 
00102     if (do_sort)
00103     {
00104         if (alen>0)
00105         {
00106             avec=new uint16_t[alen];
00107             memcpy(avec, av, sizeof(uint16_t)*alen);
00108             CMath::radix_sort(avec, alen);
00109         }
00110         else
00111             avec=NULL;
00112 
00113         if (blen>0)
00114         {
00115             bvec=new uint16_t[blen];
00116             memcpy(bvec, bv, sizeof(uint16_t)*blen);
00117             CMath::radix_sort(bvec, blen);
00118         }
00119         else
00120             bvec=NULL;
00121     }
00122     else
00123     {
00124         if ( (l->get_num_preproc() != l->get_num_preprocessed()) ||
00125                 (r->get_num_preproc() != r->get_num_preprocessed()))
00126         {
00127             SG_ERROR("not all preprocessors have been applied to training (%d/%d)"
00128                     " or test (%d/%d) data\n", l->get_num_preprocessed(), l->get_num_preproc(),
00129                     r->get_num_preprocessed(), r->get_num_preproc());
00130         }
00131     }
00132 
00133     float64_t result=0;
00134     uint8_t mask=0;
00135 
00136     for (int32_t d=0; d<degree; d++)
00137     {
00138         mask = mask | (1 << (degree-d-1));
00139         uint16_t masked=((CStringFeatures<uint16_t>*) lhs)->get_masked_symbols(0xffff, mask);
00140 
00141         int32_t left_idx=0;
00142         int32_t right_idx=0;
00143 
00144         while (left_idx < alen && right_idx < blen)
00145         {
00146             uint16_t lsym=avec[left_idx] & masked;
00147             uint16_t rsym=bvec[right_idx] & masked;
00148 
00149             if (lsym == rsym)
00150             {
00151                 int32_t old_left_idx=left_idx;
00152                 int32_t old_right_idx=right_idx;
00153 
00154                 while (left_idx<alen && (avec[left_idx] & masked) ==lsym)
00155                     left_idx++;
00156 
00157                 while (right_idx<blen && (bvec[right_idx] & masked) ==lsym)
00158                     right_idx++;
00159 
00160                 result+=weights[d]*(left_idx-old_left_idx)*(right_idx-old_right_idx);
00161             }
00162             else if (lsym<rsym)
00163                 left_idx++;
00164             else
00165                 right_idx++;
00166         }
00167     }
00168 
00169     if (do_sort)
00170     {
00171         delete[] avec;
00172         delete[] bvec;
00173     }
00174 
00175     return result;
00176 }
00177 
00178 void CWeightedCommWordStringKernel::add_to_normal(
00179     int32_t vec_idx, float64_t weight)
00180 {
00181     int32_t len=-1;
00182     CStringFeatures<uint16_t>* s=(CStringFeatures<uint16_t>*) lhs;
00183     uint16_t* vec=s->get_feature_vector(vec_idx, len);
00184 
00185     if (len>0)
00186     {
00187         for (int32_t j=0; j<len; j++)
00188         {
00189             uint8_t mask=0;
00190             int32_t offs=0;
00191             for (int32_t d=0; d<degree; d++)
00192             {
00193                 mask = mask | (1 << (degree-d-1));
00194                 int32_t idx=s->get_masked_symbols(vec[j], mask);
00195                 idx=s->shift_symbol(idx, degree-d-1);
00196                 dictionary_weights[offs + idx] += normalizer->normalize_lhs(weight*weights[d], vec_idx);
00197                 offs+=s->shift_offset(1,d+1);
00198             }
00199         }
00200 
00201         set_is_initialized(true);
00202     }
00203 }
00204 
00205 void CWeightedCommWordStringKernel::merge_normal()
00206 {
00207     ASSERT(get_is_initialized());
00208     ASSERT(use_sign==false);
00209 
00210     CStringFeatures<uint16_t>* s=(CStringFeatures<uint16_t>*) rhs;
00211     uint32_t num_symbols=(uint32_t) s->get_num_symbols();
00212     int32_t dic_size=1<<(sizeof(uint16_t)*8);
00213     float64_t* dic=new float64_t[dic_size];
00214     memset(dic, 0, sizeof(float64_t)*dic_size);
00215 
00216     for (uint32_t sym=0; sym<num_symbols; sym++)
00217     {
00218         float64_t result=0;
00219         uint8_t mask=0;
00220         int32_t offs=0;
00221         for (int32_t d=0; d<degree; d++)
00222         {
00223             mask = mask | (1 << (degree-d-1));
00224             int32_t idx=s->get_masked_symbols(sym, mask);
00225             idx=s->shift_symbol(idx, degree-d-1);
00226             result += dictionary_weights[offs + idx];
00227             offs+=s->shift_offset(1,d+1);
00228         }
00229         dic[sym]=result;
00230     }
00231 
00232     init_dictionary(1<<(sizeof(uint16_t)*8));
00233     memcpy(dictionary_weights, dic, sizeof(float64_t)*dic_size);
00234     delete[] dic;
00235 }
00236 
00237 float64_t CWeightedCommWordStringKernel::compute_optimized(int32_t i)
00238 { 
00239     if (!get_is_initialized())
00240         SG_ERROR( "CCommWordStringKernel optimization not initialized\n");
00241 
00242     ASSERT(use_sign==false);
00243 
00244     float64_t result=0;
00245     int32_t len=-1;
00246     CStringFeatures<uint16_t>* s=(CStringFeatures<uint16_t>*) rhs;
00247     uint16_t* vec=s->get_feature_vector(i, len);
00248 
00249     if (vec && len>0)
00250     {
00251         for (int32_t j=0; j<len; j++)
00252         {
00253             uint8_t mask=0;
00254             int32_t offs=0;
00255             for (int32_t d=0; d<degree; d++)
00256             {
00257                 mask = mask | (1 << (degree-d-1));
00258                 int32_t idx=s->get_masked_symbols(vec[j], mask);
00259                 idx=s->shift_symbol(idx, degree-d-1);
00260                 result += dictionary_weights[offs + idx];
00261                 offs+=s->shift_offset(1,d+1);
00262             }
00263         }
00264 
00265         result=normalizer->normalize_rhs(result, i);
00266     }
00267     return result;
00268 }
00269 
00270 float64_t* CWeightedCommWordStringKernel::compute_scoring(
00271     int32_t max_degree, int32_t& num_feat, int32_t& num_sym, float64_t* target,
00272     int32_t num_suppvec, int32_t* IDX, float64_t* alphas, bool do_init)
00273 {
00274     if (do_init)
00275         CCommWordStringKernel::init_optimization(num_suppvec, IDX, alphas);
00276 
00277     int32_t dic_size=1<<(sizeof(uint16_t)*9);
00278     float64_t* dic=new float64_t[dic_size];
00279     memcpy(dic, dictionary_weights, sizeof(float64_t)*dic_size);
00280 
00281     merge_normal();
00282     float64_t* result=CCommWordStringKernel::compute_scoring(max_degree, num_feat,
00283             num_sym, target, num_suppvec, IDX, alphas, false);
00284 
00285     init_dictionary(1<<(sizeof(uint16_t)*9));
00286     memcpy(dictionary_weights,dic,  sizeof(float64_t)*dic_size);
00287     delete[] dic;
00288 
00289     return result;
00290 }

SHOGUN Machine Learning Toolbox - Documentation