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00011 #include <shogun/lib/config.h>
00012 #include <shogun/lib/common.h>
00013 #include <shogun/io/SGIO.h>
00014 #include <shogun/distance/ChiSquareDistance.h>
00015 #include <shogun/features/Features.h>
00016
00017 using namespace shogun;
00018
00019 CChiSquareDistance::CChiSquareDistance() : CDenseDistance<float64_t>()
00020 {
00021 }
00022
00023 CChiSquareDistance::CChiSquareDistance(CDenseFeatures<float64_t>* l, CDenseFeatures<float64_t>* r)
00024 : CDenseDistance<float64_t>()
00025 {
00026 init(l, r);
00027 }
00028
00029 CChiSquareDistance::~CChiSquareDistance()
00030 {
00031 cleanup();
00032 }
00033
00034 bool CChiSquareDistance::init(CFeatures* l, CFeatures* r)
00035 {
00036 bool result=CDenseDistance<float64_t>::init(l,r);
00037
00038 return result;
00039 }
00040
00041 void CChiSquareDistance::cleanup()
00042 {
00043 }
00044
00045 float64_t CChiSquareDistance::compute(int32_t idx_a, int32_t idx_b)
00046 {
00047 int32_t alen, blen;
00048 bool afree, bfree;
00049
00050 float64_t* avec=
00051 ((CDenseFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00052 float64_t* bvec=
00053 ((CDenseFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00054
00055 ASSERT(alen==blen);
00056
00057 float64_t absTmp = 0;
00058 float64_t result=0;
00059 {
00060 for (int32_t i=0; i<alen; i++)
00061 {
00062 absTmp=fabs(avec[i])+fabs(bvec[i]);
00063 if(absTmp!=0)
00064 result+=pow((avec[i]-bvec[i]),2)/absTmp;
00065 }
00066
00067 }
00068
00069 ((CDenseFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00070 ((CDenseFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00071
00072 return result;
00073 }