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