SHOGUN
v1.1.0
|
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 Gunnar Raetsch 00008 * Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society 00009 */ 00010 00011 #include <shogun/lib/common.h> 00012 #include <shogun/io/SGIO.h> 00013 #include <shogun/kernel/SimpleLocalityImprovedStringKernel.h> 00014 #include <shogun/features/Features.h> 00015 #include <shogun/features/StringFeatures.h> 00016 00017 using namespace shogun; 00018 00019 CSimpleLocalityImprovedStringKernel::CSimpleLocalityImprovedStringKernel() 00020 : CStringKernel<char>() 00021 { 00022 init(); 00023 } 00024 00025 CSimpleLocalityImprovedStringKernel::CSimpleLocalityImprovedStringKernel( 00026 int32_t size, int32_t l, int32_t id, int32_t od) 00027 : CStringKernel<char>(size) 00028 { 00029 init(); 00030 00031 length=l; 00032 inner_degree=id; 00033 outer_degree=od; 00034 } 00035 00036 CSimpleLocalityImprovedStringKernel::CSimpleLocalityImprovedStringKernel( 00037 CStringFeatures<char>* l, CStringFeatures<char>* r, 00038 int32_t len, int32_t id, int32_t od) 00039 : CStringKernel<char>() 00040 { 00041 init(); 00042 00043 length=len; 00044 inner_degree=id; 00045 outer_degree=od; 00046 00047 init(l, r); 00048 } 00049 00050 CSimpleLocalityImprovedStringKernel::~CSimpleLocalityImprovedStringKernel() 00051 { 00052 cleanup(); 00053 } 00054 00055 bool CSimpleLocalityImprovedStringKernel::init(CFeatures* l, CFeatures* r) 00056 { 00057 bool result = CStringKernel<char>::init(l,r); 00058 00059 if (!result) 00060 return false; 00061 const int32_t num_features = ((CStringFeatures<char>*) l)->get_max_vector_length(); 00062 const int32_t PYRAL = 2 * length - 1; // total window length 00063 const int32_t pyra_len = num_features-PYRAL+1; 00064 const int32_t pyra_len2 = (int32_t) pyra_len/2; 00065 00066 SG_FREE(pyramid_weights); 00067 00068 pyramid_weights = SG_MALLOC(float64_t, pyra_len); 00069 num_pyramid_weights=pyra_len; 00070 00071 SG_INFO("initializing pyramid weights: size=%ld length=%i\n", 00072 num_features, length); 00073 00074 float64_t PYRAL_pot; 00075 int32_t DEGREE1_1 = (inner_degree & 0x1)==0; 00076 int32_t DEGREE1_1n = (inner_degree & ~0x1)!=0; 00077 int32_t DEGREE1_2 = (inner_degree & 0x2)!=0; 00078 int32_t DEGREE1_3 = (inner_degree & ~0x3)!=0; 00079 int32_t DEGREE1_4 = (inner_degree & 0x4)!=0; 00080 { 00081 float64_t PYRAL_ = PYRAL; 00082 PYRAL_pot = DEGREE1_1 ? 1.0 : PYRAL_; 00083 if (DEGREE1_1n) 00084 { 00085 PYRAL_ *= PYRAL_; 00086 if (DEGREE1_2) 00087 PYRAL_pot *= PYRAL_; 00088 if (DEGREE1_3) 00089 { 00090 PYRAL_ *= PYRAL_; 00091 if (DEGREE1_4) 00092 PYRAL_pot *= PYRAL_; 00093 } 00094 } 00095 } 00096 00097 { 00098 int32_t j; 00099 for (j = 0; j < pyra_len; j++) 00100 pyramid_weights[j] = 4*((float64_t)((j < pyra_len2)? j+1 : pyra_len-j))/((float64_t)pyra_len); 00101 for (j = 0; j < pyra_len; j++) 00102 pyramid_weights[j] /= PYRAL_pot; 00103 } 00104 00105 return init_normalizer(); 00106 } 00107 00108 void CSimpleLocalityImprovedStringKernel::cleanup() 00109 { 00110 SG_FREE(pyramid_weights); 00111 pyramid_weights = NULL; 00112 num_pyramid_weights = 0; 00113 00114 CKernel::cleanup(); 00115 } 00116 00117 float64_t CSimpleLocalityImprovedStringKernel::dot_pyr (const char* const x1, 00118 const char* const x2, const int32_t NOF_NTS, const int32_t NTWIDTH, 00119 const int32_t DEGREE1, const int32_t DEGREE2, float64_t *pyra) 00120 { 00121 const int32_t PYRAL = 2*NTWIDTH-1; // total window length 00122 int32_t pyra_len, pyra_len2; 00123 float64_t pot, PYRAL_pot; 00124 float64_t sum; 00125 int32_t DEGREE1_1 = (DEGREE1 & 0x1)==0; 00126 int32_t DEGREE1_1n = (DEGREE1 & ~0x1)!=0; 00127 int32_t DEGREE1_2 = (DEGREE1 & 0x2)!=0; 00128 int32_t DEGREE1_3 = (DEGREE1 & ~0x3)!=0; 00129 int32_t DEGREE1_4 = (DEGREE1 & 0x4)!=0; 00130 { 00131 float64_t PYRAL_ = PYRAL; 00132 PYRAL_pot = DEGREE1_1 ? 1.0 : PYRAL_; 00133 if (DEGREE1_1n) 00134 { 00135 PYRAL_ *= PYRAL_; 00136 if (DEGREE1_2) PYRAL_pot *= PYRAL_; 00137 if (DEGREE1_3) 00138 { 00139 PYRAL_ *= PYRAL_; 00140 if (DEGREE1_4) PYRAL_pot *= PYRAL_; 00141 } 00142 } 00143 } 00144 00145 ASSERT((DEGREE1 & ~0x7) == 0); 00146 ASSERT((DEGREE2 & ~0x7) == 0); 00147 00148 pyra_len = NOF_NTS-PYRAL+1; 00149 pyra_len2 = (int32_t) pyra_len/2; 00150 { 00151 int32_t j; 00152 for (j = 0; j < pyra_len; j++) 00153 pyra[j] = 4*((float64_t)((j < pyra_len2) ? j+1 : pyra_len-j))/((float64_t)pyra_len); 00154 for (j = 0; j < pyra_len; j++) 00155 pyra[j] /= PYRAL_pot; 00156 } 00157 00158 register int32_t conv; 00159 register int32_t i; 00160 register int32_t j; 00161 00162 sum = 0.0; 00163 conv = 0; 00164 for (j = 0; j < PYRAL; j++) 00165 conv += (x1[j] == x2[j]) ? 1 : 0; 00166 00167 for (i = 0; i < NOF_NTS-PYRAL+1; i++) 00168 { 00169 register float64_t pot2; 00170 if (i>0) 00171 conv += ((x1[i+PYRAL-1] == x2[i+PYRAL-1]) ? 1 : 0 ) - 00172 ((x1[i-1] == x2[i-1]) ? 1 : 0); 00173 { /* potencing of conv -- float64_t is faster*/ 00174 register float64_t conv2 = conv; 00175 pot2 = (DEGREE1_1) ? 1.0 : conv2; 00176 if (DEGREE1_1n) 00177 { 00178 conv2 *= conv2; 00179 if (DEGREE1_2) 00180 pot2 *= conv2; 00181 if (DEGREE1_3 && DEGREE1_4) 00182 pot2 *= conv2*conv2; 00183 } 00184 } 00185 sum += pot2*pyra[i]; 00186 } 00187 00188 pot = ((DEGREE2 & 0x1) == 0) ? 1.0 : sum; 00189 if ((DEGREE2 & ~0x1) != 0) 00190 { 00191 sum *= sum; 00192 if ((DEGREE2 & 0x2) != 0) 00193 pot *= sum; 00194 if ((DEGREE2 & ~0x3) != 0) 00195 { 00196 sum *= sum; 00197 if ((DEGREE2 & 0x4) != 0) 00198 pot *= sum; 00199 } 00200 } 00201 return pot; 00202 } 00203 00204 float64_t CSimpleLocalityImprovedStringKernel::compute( 00205 int32_t idx_a, int32_t idx_b) 00206 { 00207 int32_t alen, blen; 00208 bool free_avec, free_bvec; 00209 00210 char* avec = ((CStringFeatures<char>*) lhs)->get_feature_vector(idx_a, alen, free_avec); 00211 char* bvec = ((CStringFeatures<char>*) rhs)->get_feature_vector(idx_b, blen, free_bvec); 00212 00213 // can only deal with strings of same length 00214 ASSERT(alen==blen); 00215 00216 float64_t dpt; 00217 00218 dpt = dot_pyr(avec, bvec, alen, length, inner_degree, outer_degree, pyramid_weights); 00219 dpt = dpt / pow((float64_t) alen, (float64_t) outer_degree); 00220 00221 ((CStringFeatures<char>*) lhs)->free_feature_vector(avec, idx_a, free_avec); 00222 ((CStringFeatures<char>*) rhs)->free_feature_vector(bvec, idx_b, free_bvec); 00223 return (float64_t) dpt; 00224 } 00225 00226 void CSimpleLocalityImprovedStringKernel::init() 00227 { 00228 length = 3; 00229 inner_degree = 3; 00230 outer_degree = 1; 00231 pyramid_weights=NULL; 00232 num_pyramid_weights=0; 00233 00234 m_parameters->add(&length, "length", "Window Length."); 00235 m_parameters->add(&inner_degree, "inner_degree", "Inner degree."); 00236 m_parameters->add(&outer_degree, "outer_degree", "Outer degree."); 00237 00238 m_parameters->add_vector(&pyramid_weights, &num_pyramid_weights, 00239 "pyramid_weights", "Pyramid weights."); 00240 }