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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 #include <shogun/features/SimpleFeatures.h>
00017
00018 using namespace shogun;
00019
00020 CCosineDistance::CCosineDistance()
00021 : CSimpleDistance<float64_t>()
00022 {
00023 }
00024
00025 CCosineDistance::CCosineDistance(CSimpleFeatures<float64_t>* l, CSimpleFeatures<float64_t>* r)
00026 : CSimpleDistance<float64_t>()
00027 {
00028 init(l, r);
00029 }
00030
00031 CCosineDistance::~CCosineDistance()
00032 {
00033 cleanup();
00034 }
00035
00036 bool CCosineDistance::init(CFeatures* l, CFeatures* r)
00037 {
00038 return CSimpleDistance<float64_t>::init(l,r);
00039 }
00040
00041 void CCosineDistance::cleanup()
00042 {
00043 }
00044
00045 float64_t CCosineDistance::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 ((CSimpleFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00052 float64_t* bvec=
00053 ((CSimpleFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00054
00055 ASSERT(alen==blen);
00056 float64_t s=0;
00057 float64_t ab=0;
00058 float64_t sa=0;
00059 float64_t sb=0;
00060 {
00061 for (int32_t i=0; i<alen; i++)
00062 {
00063 ab+=avec[i]*bvec[i];
00064 sa+=pow(fabs(avec[i]),2);
00065 sb+=pow(fabs(bvec[i]),2);
00066 }
00067 }
00068
00069 ((CSimpleFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00070 ((CSimpleFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00071
00072 s=sqrt(sa)*sqrt(sb);
00073
00074
00075 if(s==0)
00076 return 0;
00077
00078 s=1-ab/s;
00079 if(s<0)
00080 return 0;
00081 else
00082 return s ;
00083 }