SHOGUN
v1.1.0
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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/mathematics/Math.h> 00013 #include <shogun/io/SGIO.h> 00014 #include <shogun/kernel/MatchWordStringKernel.h> 00015 #include <shogun/kernel/AvgDiagKernelNormalizer.h> 00016 #include <shogun/features/StringFeatures.h> 00017 00018 using namespace shogun; 00019 00020 CMatchWordStringKernel::CMatchWordStringKernel() : CStringKernel<uint16_t>() 00021 { 00022 init(); 00023 } 00024 00025 CMatchWordStringKernel::CMatchWordStringKernel(int32_t size, int32_t d) 00026 : CStringKernel<uint16_t>(size) 00027 { 00028 init(); 00029 degree=d; 00030 } 00031 00032 CMatchWordStringKernel::CMatchWordStringKernel( 00033 CStringFeatures<uint16_t>* l, CStringFeatures<uint16_t>* r, int32_t d) 00034 : CStringKernel<uint16_t>() 00035 { 00036 init(); 00037 degree=d; 00038 init(l, r); 00039 } 00040 00041 CMatchWordStringKernel::~CMatchWordStringKernel() 00042 { 00043 cleanup(); 00044 } 00045 00046 bool CMatchWordStringKernel::init(CFeatures* l, CFeatures* r) 00047 { 00048 CStringKernel<uint16_t>::init(l, r); 00049 return init_normalizer(); 00050 } 00051 00052 float64_t CMatchWordStringKernel::compute(int32_t idx_a, int32_t idx_b) 00053 { 00054 int32_t alen, blen; 00055 bool free_avec, free_bvec; 00056 00057 uint16_t* avec=((CStringFeatures<uint16_t>*) lhs)->get_feature_vector(idx_a, alen, free_avec); 00058 uint16_t* bvec=((CStringFeatures<uint16_t>*) rhs)->get_feature_vector(idx_b, blen, free_bvec); 00059 // can only deal with strings of same length 00060 ASSERT(alen==blen); 00061 00062 float64_t sum=0; 00063 for (int32_t i=0; i<alen; i++) 00064 sum+= (avec[i]==bvec[i]) ? 1 : 0; 00065 00066 ((CStringFeatures<uint16_t>*) lhs)->free_feature_vector(avec, idx_a, free_avec); 00067 ((CStringFeatures<uint16_t>*) rhs)->free_feature_vector(bvec, idx_b, free_bvec); 00068 00069 return CMath::pow(sum, degree); 00070 } 00071 00072 void CMatchWordStringKernel::init() 00073 { 00074 degree=0; 00075 set_normalizer(new CAvgDiagKernelNormalizer()); 00076 m_parameters->add(°ree, "degree", "Degree of poly kernel"); 00077 }