SHOGUN
v3.2.0
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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) 1999-2009 Soeren Sonnenburg 00008 * Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society 00009 */ 00010 00011 #include <shogun/lib/common.h> 00012 #include <shogun/kernel/WeightedDegreeRBFKernel.h> 00013 #include <shogun/features/Features.h> 00014 #include <shogun/io/SGIO.h> 00015 00016 using namespace shogun; 00017 00018 CWeightedDegreeRBFKernel::CWeightedDegreeRBFKernel() 00019 : CDotKernel(), width(1), degree(1), weights(0) 00020 { 00021 } 00022 00023 00024 CWeightedDegreeRBFKernel::CWeightedDegreeRBFKernel(int32_t size, float64_t w, int32_t d, int32_t nof_prop) 00025 : CDotKernel(size), width(w), degree(d), nof_properties(nof_prop), weights(0) 00026 { 00027 init_wd_weights(); 00028 } 00029 00030 CWeightedDegreeRBFKernel::CWeightedDegreeRBFKernel( 00031 CDenseFeatures<float64_t>* l, CDenseFeatures<float64_t>* r, float64_t w, int32_t d, int32_t nof_prop, int32_t size) 00032 : CDotKernel(size), width(w), degree(d), nof_properties(nof_prop), weights(0) 00033 { 00034 init_wd_weights(); 00035 init(l,r); 00036 } 00037 00038 CWeightedDegreeRBFKernel::~CWeightedDegreeRBFKernel() 00039 { 00040 SG_FREE(weights); 00041 weights=NULL; 00042 } 00043 00044 bool CWeightedDegreeRBFKernel::init(CFeatures* l, CFeatures* r) 00045 { 00046 CDotKernel::init(l, r); 00047 SG_DEBUG("Initialized WeightedDegreeRBFKernel (%p).\n", this) 00048 return init_normalizer(); 00049 } 00050 00051 bool CWeightedDegreeRBFKernel::init_wd_weights() 00052 { 00053 ASSERT(degree>0) 00054 00055 if (weights!=0) SG_FREE(weights); 00056 weights=SG_MALLOC(float64_t, degree); 00057 if (weights) 00058 { 00059 int32_t i; 00060 float64_t sum=0; 00061 for (i=0; i<degree; i++) 00062 { 00063 weights[i]=degree-i; 00064 sum+=weights[i]; 00065 } 00066 for (i=0; i<degree; i++) 00067 weights[i]/=sum; 00068 00069 SG_DEBUG("Initialized weights for WeightedDegreeRBFKernel (%p).\n", this) 00070 return true; 00071 } 00072 else 00073 return false; 00074 } 00075 00076 00077 float64_t CWeightedDegreeRBFKernel::compute(int32_t idx_a, int32_t idx_b) 00078 { 00079 int32_t alen, blen; 00080 bool afree, bfree; 00081 00082 float64_t* avec=((CDenseFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree); 00083 float64_t* bvec=((CDenseFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree); 00084 ASSERT(alen==blen) 00085 ASSERT(alen%nof_properties == 0) 00086 00087 float64_t result=0; 00088 00089 for (int32_t i=0; i<alen; i+=nof_properties) 00090 { 00091 float64_t resulti = 0.0; 00092 00093 for (int32_t d=0; (i+(d*nof_properties)<alen) && (d<degree); d++) 00094 { 00095 float64_t resultid = 0.0; 00096 int32_t limit = (d + 1 ) * nof_properties; 00097 for (int32_t k=0; k < limit; k++) 00098 { 00099 resultid+=CMath::sq(avec[i+k]-bvec[i+k]); 00100 } 00101 00102 resulti += weights[d] * exp(-resultid/width); 00103 } 00104 00105 result+=resulti ; 00106 } 00107 00108 return result; 00109 }