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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/JensenMetric.h>
00015 #include <shogun/features/Features.h>
00016 #include <shogun/features/SimpleFeatures.h>
00017
00018 using namespace shogun;
00019
00020 CJensenMetric::CJensenMetric() : CSimpleDistance<float64_t>()
00021 {
00022 }
00023
00024 CJensenMetric::CJensenMetric(CSimpleFeatures<float64_t>* l, CSimpleFeatures<float64_t>* r)
00025 : CSimpleDistance<float64_t>()
00026 {
00027 init(l, r);
00028 }
00029
00030 CJensenMetric::~CJensenMetric()
00031 {
00032 cleanup();
00033 }
00034
00035 bool CJensenMetric::init(CFeatures* l, CFeatures* r)
00036 {
00037 return CSimpleDistance<float64_t>::init(l,r);
00038 }
00039
00040 void CJensenMetric::cleanup()
00041 {
00042 }
00043
00044 float64_t CJensenMetric::compute(int32_t idx_a, int32_t idx_b)
00045 {
00046 int32_t alen, blen;
00047 bool afree, bfree;
00048
00049 float64_t* avec=
00050 ((CSimpleFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00051 float64_t* bvec=
00052 ((CSimpleFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00053
00054 ASSERT(alen==blen);
00055
00056 float64_t absTmp = 0;
00057 float64_t result=0;
00058 {
00059 for (int32_t i=0; i<alen; i++)
00060 {
00061 absTmp=0.5*(avec[i]+bvec[i]);
00062 if (absTmp>0)
00063 {
00064 if(avec[i]>0)
00065 result+=avec[i]*log(avec[i]/absTmp);
00066 if(bvec[i]>0)
00067 result+=bvec[i]*log(bvec[i]/absTmp);
00068 }
00069 }
00070
00071 }
00072
00073 ((CSimpleFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00074 ((CSimpleFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00075
00076
00077 return result;
00078 }