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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/CosineDistance.h>
00015 #include <shogun/features/Features.h>
00016
00017 using namespace shogun;
00018
00019 CCosineDistance::CCosineDistance()
00020 : CDenseDistance<float64_t>()
00021 {
00022 }
00023
00024 CCosineDistance::CCosineDistance(CDenseFeatures<float64_t>* l, CDenseFeatures<float64_t>* r)
00025 : CDenseDistance<float64_t>()
00026 {
00027 init(l, r);
00028 }
00029
00030 CCosineDistance::~CCosineDistance()
00031 {
00032 cleanup();
00033 }
00034
00035 bool CCosineDistance::init(CFeatures* l, CFeatures* r)
00036 {
00037 return CDenseDistance<float64_t>::init(l,r);
00038 }
00039
00040 void CCosineDistance::cleanup()
00041 {
00042 }
00043
00044 float64_t CCosineDistance::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 ((CDenseFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00051 float64_t* bvec=
00052 ((CDenseFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00053
00054 ASSERT(alen==blen);
00055 float64_t s=0;
00056 float64_t ab=0;
00057 float64_t sa=0;
00058 float64_t sb=0;
00059 {
00060 for (int32_t i=0; i<alen; i++)
00061 {
00062 ab+=avec[i]*bvec[i];
00063 sa+=pow(fabs(avec[i]),2);
00064 sb+=pow(fabs(bvec[i]),2);
00065 }
00066 }
00067
00068 ((CDenseFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00069 ((CDenseFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00070
00071 s=sqrt(sa)*sqrt(sb);
00072
00073
00074 if(s==0)
00075 return 0;
00076
00077 s=1-ab/s;
00078 if(s<0)
00079 return 0;
00080 else
00081 return s ;
00082 }