CosineDistance.cpp
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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/RealFeatures.h"
00017
00018 CCosineDistance::CCosineDistance()
00019 : CSimpleDistance<float64_t>()
00020 {
00021 }
00022
00023 CCosineDistance::CCosineDistance(CRealFeatures* l, CRealFeatures* r)
00024 : CSimpleDistance<float64_t>()
00025 {
00026 init(l, r);
00027 }
00028
00029 CCosineDistance::~CCosineDistance()
00030 {
00031 cleanup();
00032 }
00033
00034 bool CCosineDistance::init(CFeatures* l, CFeatures* r)
00035 {
00036 bool result=CSimpleDistance<float64_t>::init(l,r);
00037
00038 return result;
00039 }
00040
00041 void CCosineDistance::cleanup()
00042 {
00043 }
00044
00045 bool CCosineDistance::load_init(FILE* src)
00046 {
00047 return false;
00048 }
00049
00050 bool CCosineDistance::save_init(FILE* dest)
00051 {
00052 return false;
00053 }
00054
00055 float64_t CCosineDistance::compute(int32_t idx_a, int32_t idx_b)
00056 {
00057 int32_t alen, blen;
00058 bool afree, bfree;
00059
00060 float64_t* avec=
00061 ((CRealFeatures*) lhs)->get_feature_vector(idx_a, alen, afree);
00062 float64_t* bvec=
00063 ((CRealFeatures*) rhs)->get_feature_vector(idx_b, blen, bfree);
00064
00065 ASSERT(alen==blen);
00066 float64_t s=0;
00067 float64_t ab=0;
00068 float64_t sa=0;
00069 float64_t sb=0;
00070 {
00071 for (int32_t i=0; i<alen; i++)
00072 {
00073 ab+=avec[i]*bvec[i];
00074 sa+=pow(fabs(avec[i]),2);
00075 sb+=pow(fabs(bvec[i]),2);
00076 }
00077 }
00078
00079 ((CRealFeatures*) lhs)->free_feature_vector(avec, idx_a, afree);
00080 ((CRealFeatures*) rhs)->free_feature_vector(bvec, idx_b, bfree);
00081
00082 s=sqrt(sa)*sqrt(sb);
00083
00084
00085 if(s==0)
00086 return 0;
00087
00088 s=1-ab/s;
00089 if(s<0)
00090 return 0;
00091 else
00092 return s ;
00093 }