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00011 #include "lib/common.h"
00012 #include "lib/io.h"
00013 #include "kernel/PolyMatchWordStringKernel.h"
00014 #include "kernel/SqrtDiagKernelNormalizer.h"
00015 #include "features/Features.h"
00016 #include "features/StringFeatures.h"
00017
00018 using namespace shogun;
00019
00020 CPolyMatchWordStringKernel::CPolyMatchWordStringKernel(int32_t size, int32_t d, bool i)
00021 : CStringKernel<uint16_t>(size),degree(d),inhomogene(i)
00022 {
00023 set_normalizer(new CSqrtDiagKernelNormalizer());
00024 }
00025
00026 CPolyMatchWordStringKernel::CPolyMatchWordStringKernel(
00027 CStringFeatures<uint16_t>* l, CStringFeatures<uint16_t>* r, int32_t d, bool i)
00028 : CStringKernel<uint16_t>(10),degree(d),inhomogene(i)
00029 {
00030 set_normalizer(new CSqrtDiagKernelNormalizer());
00031 init(l, r);
00032 }
00033
00034 CPolyMatchWordStringKernel::~CPolyMatchWordStringKernel()
00035 {
00036 cleanup();
00037 }
00038
00039 bool CPolyMatchWordStringKernel::init(CFeatures* l, CFeatures* r)
00040 {
00041 CStringKernel<uint16_t>::init(l,r);
00042 return init_normalizer();
00043 }
00044
00045 void CPolyMatchWordStringKernel::cleanup()
00046 {
00047 CKernel::cleanup();
00048 }
00049
00050 float64_t CPolyMatchWordStringKernel::compute(int32_t idx_a, int32_t idx_b)
00051 {
00052 int32_t alen, blen;
00053 bool free_avec, free_bvec;
00054
00055 uint16_t* avec=((CStringFeatures<uint16_t>*) lhs)->get_feature_vector(idx_a, alen, free_avec);
00056 uint16_t* bvec=((CStringFeatures<uint16_t>*) rhs)->get_feature_vector(idx_b, blen, free_bvec);
00057
00058 ASSERT(alen==blen);
00059
00060 int32_t sum=0;
00061
00062 for (int32_t i=0; i<alen; i++)
00063 sum+= (avec[i]==bvec[i]) ? 1 : 0;
00064
00065 if (inhomogene)
00066 sum+=1;
00067
00068 float64_t result=sum;
00069
00070 for (int32_t j=1; j<degree; j++)
00071 result*=sum;
00072
00073 ((CStringFeatures<uint16_t>*) lhs)->free_feature_vector(avec, idx_a, free_avec);
00074 ((CStringFeatures<uint16_t>*) rhs)->free_feature_vector(bvec, idx_b, free_bvec);
00075 return result;
00076 }