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00011 #include "lib/config.h"
00012 #include "lib/common.h"
00013 #include "lib/io.h"
00014 #include "distance/CosineDistance.h"
00015 #include "features/Features.h"
00016 #include "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 bool result=CSimpleDistance<float64_t>::init(l,r);
00039
00040 return result;
00041 }
00042
00043 void CCosineDistance::cleanup()
00044 {
00045 }
00046
00047 float64_t CCosineDistance::compute(int32_t idx_a, int32_t idx_b)
00048 {
00049 int32_t alen, blen;
00050 bool afree, bfree;
00051
00052 float64_t* avec=
00053 ((CSimpleFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00054 float64_t* bvec=
00055 ((CSimpleFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00056
00057 ASSERT(alen==blen);
00058 float64_t s=0;
00059 float64_t ab=0;
00060 float64_t sa=0;
00061 float64_t sb=0;
00062 {
00063 for (int32_t i=0; i<alen; i++)
00064 {
00065 ab+=avec[i]*bvec[i];
00066 sa+=pow(fabs(avec[i]),2);
00067 sb+=pow(fabs(bvec[i]),2);
00068 }
00069 }
00070
00071 ((CSimpleFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree);
00072 ((CSimpleFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00073
00074 s=sqrt(sa)*sqrt(sb);
00075
00076
00077 if(s==0)
00078 return 0;
00079
00080 s=1-ab/s;
00081 if(s<0)
00082 return 0;
00083 else
00084 return s ;
00085 }