SparseEuclidianDistance.cpp
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00011 #include "lib/common.h"
00012 #include "lib/io.h"
00013 #include "distance/SparseEuclidianDistance.h"
00014 #include "features/Features.h"
00015 #include "features/SparseFeatures.h"
00016
00017 using namespace shogun;
00018
00019 CSparseEuclidianDistance::CSparseEuclidianDistance()
00020 : CSparseDistance<float64_t>(), sq_lhs(NULL), sq_rhs(NULL)
00021 {
00022 }
00023
00024 CSparseEuclidianDistance::CSparseEuclidianDistance(
00025 CSparseFeatures<float64_t>* l, CSparseFeatures<float64_t>* r)
00026 : CSparseDistance<float64_t>(), sq_lhs(NULL), sq_rhs(NULL)
00027 {
00028 init(l, r);
00029 }
00030
00031 CSparseEuclidianDistance::~CSparseEuclidianDistance()
00032 {
00033 cleanup();
00034 }
00035
00036 bool CSparseEuclidianDistance::init(CFeatures* l, CFeatures* r)
00037 {
00038 CSparseDistance<float64_t>::init(l, r);
00039
00040 cleanup();
00041
00042 sq_lhs=new float64_t[lhs->get_num_vectors()];
00043 sq_lhs=((CSparseFeatures<float64_t>*) lhs)->compute_squared(sq_lhs);
00044
00045 if (lhs==rhs)
00046 sq_rhs=sq_lhs;
00047 else
00048 {
00049 sq_rhs=new float64_t[rhs->get_num_vectors()];
00050 sq_rhs=((CSparseFeatures<float64_t>*) rhs)->compute_squared(sq_rhs);
00051 }
00052
00053 return true;
00054 }
00055
00056 void CSparseEuclidianDistance::cleanup()
00057 {
00058 if (sq_lhs != sq_rhs)
00059 delete[] sq_rhs;
00060 sq_rhs = NULL;
00061
00062 delete[] sq_lhs;
00063 sq_lhs = NULL;
00064 }
00065
00066 float64_t CSparseEuclidianDistance::compute(int32_t idx_a, int32_t idx_b)
00067 {
00068 float64_t result=((CSparseFeatures<float64_t>*) lhs)->compute_squared_norm(
00069 (CSparseFeatures<float64_t>*) lhs, sq_lhs, idx_a,
00070 (CSparseFeatures<float64_t>*) rhs, sq_rhs, idx_b);
00071
00072 return CMath::sqrt(result);
00073 }