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/io/SGIO.h> 00013 #include <shogun/kernel/string/PolyMatchStringKernel.h> 00014 #include <shogun/kernel/normalizer/SqrtDiagKernelNormalizer.h> 00015 #include <shogun/features/Features.h> 00016 #include <shogun/features/StringFeatures.h> 00017 00018 using namespace shogun; 00019 00020 CPolyMatchStringKernel::CPolyMatchStringKernel() 00021 : CStringKernel<char>() 00022 { 00023 init(); 00024 } 00025 00026 CPolyMatchStringKernel::CPolyMatchStringKernel(int32_t size, int32_t d, bool i) 00027 : CStringKernel<char>(size) 00028 { 00029 init(); 00030 00031 degree=d; 00032 inhomogene=i; 00033 } 00034 00035 CPolyMatchStringKernel::CPolyMatchStringKernel( 00036 CStringFeatures<char>* l, CStringFeatures<char>* r, int32_t d, bool i) 00037 : CStringKernel<char>(10) 00038 { 00039 init(); 00040 00041 degree=d; 00042 inhomogene=i; 00043 00044 init(l, r); 00045 } 00046 00047 CPolyMatchStringKernel::~CPolyMatchStringKernel() 00048 { 00049 cleanup(); 00050 } 00051 00052 bool CPolyMatchStringKernel::init(CFeatures* l, CFeatures* r) 00053 { 00054 CStringKernel<char>::init(l, r); 00055 return init_normalizer(); 00056 } 00057 00058 void CPolyMatchStringKernel::cleanup() 00059 { 00060 CKernel::cleanup(); 00061 } 00062 00063 float64_t CPolyMatchStringKernel::compute(int32_t idx_a, int32_t idx_b) 00064 { 00065 int32_t i, alen, blen, sum; 00066 bool free_avec, free_bvec; 00067 00068 char* avec = ((CStringFeatures<char>*) lhs)->get_feature_vector(idx_a, alen, free_avec); 00069 char* bvec = ((CStringFeatures<char>*) rhs)->get_feature_vector(idx_b, blen, free_bvec); 00070 00071 ASSERT(alen==blen) 00072 for (i = 0, sum = inhomogene; i<alen; i++) 00073 { 00074 if (avec[i]==bvec[i]) 00075 sum++; 00076 } 00077 float64_t result = ((float64_t) sum); 00078 00079 if (rescaling) 00080 result/=alen; 00081 00082 ((CStringFeatures<char>*) lhs)->free_feature_vector(avec, idx_a, free_avec); 00083 ((CStringFeatures<char>*) rhs)->free_feature_vector(bvec, idx_b, free_bvec); 00084 return CMath::pow(result , degree); 00085 } 00086 00087 void CPolyMatchStringKernel::init() 00088 { 00089 degree=0; 00090 inhomogene=false; 00091 rescaling=false; 00092 set_normalizer(new CSqrtDiagKernelNormalizer()); 00093 00094 SG_ADD(°ree, "degree", "Degree of poly-kernel.", MS_AVAILABLE); 00095 SG_ADD(&inhomogene, "inhomogene", "True for inhomogene poly-kernel.", 00096 MS_NOT_AVAILABLE); 00097 SG_ADD(&rescaling, "rescaling", 00098 "True to rescale kernel with string length.", MS_AVAILABLE); 00099 }