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) 1999-2009 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/features/SimpleFeatures.h> 00015 #include <shogun/io/SGIO.h> 00016 00017 using namespace shogun; 00018 00019 CWeightedDegreeRBFKernel::CWeightedDegreeRBFKernel() 00020 : CDotKernel(), width(1), degree(1), weights(0) 00021 { 00022 } 00023 00024 00025 CWeightedDegreeRBFKernel::CWeightedDegreeRBFKernel(int32_t size, float64_t w, int32_t d, int32_t nof_prop) 00026 : CDotKernel(size), width(w), degree(d), nof_properties(nof_prop), weights(0) 00027 { 00028 init_wd_weights(); 00029 } 00030 00031 CWeightedDegreeRBFKernel::CWeightedDegreeRBFKernel( 00032 CSimpleFeatures<float64_t>* l, CSimpleFeatures<float64_t>* r, float64_t w, int32_t d, int32_t nof_prop, int32_t size) 00033 : CDotKernel(size), width(w), degree(d), nof_properties(nof_prop), weights(0) 00034 { 00035 init_wd_weights(); 00036 init(l,r); 00037 } 00038 00039 CWeightedDegreeRBFKernel::~CWeightedDegreeRBFKernel() 00040 { 00041 SG_FREE(weights); 00042 weights=NULL; 00043 } 00044 00045 bool CWeightedDegreeRBFKernel::init(CFeatures* l, CFeatures* r) 00046 { 00047 CDotKernel::init(l, r); 00048 SG_DEBUG("Initialized WeightedDegreeRBFKernel (%p).\n", this); 00049 return init_normalizer(); 00050 } 00051 00052 bool CWeightedDegreeRBFKernel::init_wd_weights() 00053 { 00054 ASSERT(degree>0); 00055 00056 if (weights!=0) SG_FREE(weights); 00057 weights=SG_MALLOC(float64_t, degree); 00058 if (weights) 00059 { 00060 int32_t i; 00061 float64_t sum=0; 00062 for (i=0; i<degree; i++) 00063 { 00064 weights[i]=degree-i; 00065 sum+=weights[i]; 00066 } 00067 for (i=0; i<degree; i++) 00068 weights[i]/=sum; 00069 00070 SG_DEBUG("Initialized weights for WeightedDegreeRBFKernel (%p).\n", this); 00071 return true; 00072 } 00073 else 00074 return false; 00075 } 00076 00077 00078 float64_t CWeightedDegreeRBFKernel::compute(int32_t idx_a, int32_t idx_b) 00079 { 00080 int32_t alen, blen; 00081 bool afree, bfree; 00082 00083 float64_t* avec=((CSimpleFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree); 00084 float64_t* bvec=((CSimpleFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree); 00085 ASSERT(alen==blen); 00086 ASSERT(alen%nof_properties == 0); 00087 00088 float64_t result=0; 00089 00090 for (int32_t i=0; i<alen; i+=nof_properties) 00091 { 00092 float64_t resulti = 0.0; 00093 00094 for (int32_t d=0; (i+(d*nof_properties)<alen) && (d<degree); d++) 00095 { 00096 float64_t resultid = 0.0; 00097 int32_t limit = (d + 1 ) * nof_properties; 00098 for (int32_t k=0; k < limit; k++) 00099 { 00100 resultid+=CMath::sq(avec[i+k]-bvec[i+k]); 00101 } 00102 00103 resulti += weights[d] * exp(-resultid/width); 00104 } 00105 00106 result+=resulti ; 00107 } 00108 00109 return result; 00110 }