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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 #include <shogun/features/SimpleFeatures.h>
00017
00018 using namespace shogun;
00019
00020 CChiSquareDistance::CChiSquareDistance() : CSimpleDistance<float64_t>()
00021 {
00022 }
00023
00024 CChiSquareDistance::CChiSquareDistance(CSimpleFeatures<float64_t>* l, CSimpleFeatures<float64_t>* r)
00025 : CSimpleDistance<float64_t>()
00026 {
00027 init(l, r);
00028 }
00029
00030 CChiSquareDistance::~CChiSquareDistance()
00031 {
00032 cleanup();
00033 }
00034
00035 bool CChiSquareDistance::init(CFeatures* l, CFeatures* r)
00036 {
00037 bool result=CSimpleDistance<float64_t>::init(l,r);
00038
00039 return result;
00040 }
00041
00042 void CChiSquareDistance::cleanup()
00043 {
00044 }
00045
00046 float64_t CChiSquareDistance::compute(int32_t idx_a, int32_t idx_b)
00047 {
00048 int32_t alen, blen;
00049 bool afree, bfree;
00050
00051 float64_t* avec=
00052 ((CSimpleFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00053 float64_t* bvec=
00054 ((CSimpleFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00055
00056 ASSERT(alen==blen);
00057
00058 float64_t absTmp = 0;
00059 float64_t result=0;
00060 {
00061 for (int32_t i=0; i<alen; i++)
00062 {
00063 absTmp=fabs(avec[i])+fabs(bvec[i]);
00064 if(absTmp!=0)
00065 result+=pow((avec[i]-bvec[i]),2)/absTmp;
00066 }
00067
00068 }
00069
00070 ((CSimpleFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00071 ((CSimpleFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00072
00073 return result;
00074 }