ManhattanWordDistance.cpp
Go to the documentation of this file.00001
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00012 #include "lib/common.h"
00013 #include "distance/ManhattanWordDistance.h"
00014 #include "features/Features.h"
00015 #include "features/StringFeatures.h"
00016 #include "lib/io.h"
00017
00018 CManhattanWordDistance::CManhattanWordDistance()
00019 : CStringDistance<WORD>()
00020 {
00021 SG_DEBUG("CManhattanWordDistance created");
00022 dictionary_size= 1<<(sizeof(WORD)*8);
00023 dictionary_weights = new DREAL[dictionary_size];
00024 SG_DEBUG( "using dictionary of %d bytes\n", dictionary_size);
00025 }
00026
00027 CManhattanWordDistance::CManhattanWordDistance(
00028 CStringFeatures<WORD>* l, CStringFeatures<WORD>* r)
00029 : CStringDistance<WORD>()
00030 {
00031 SG_DEBUG("CManhattanWordDistance created");
00032 dictionary_size= 1<<(sizeof(WORD)*8);
00033 dictionary_weights = new DREAL[dictionary_size];
00034 SG_DEBUG( "using dictionary of %d bytes\n", dictionary_size);
00035
00036 init(l, r);
00037 }
00038
00039 CManhattanWordDistance::~CManhattanWordDistance()
00040 {
00041 cleanup();
00042
00043 delete[] dictionary_weights;
00044 }
00045
00046 bool CManhattanWordDistance::init(CFeatures* l, CFeatures* r)
00047 {
00048 bool result=CStringDistance<WORD>::init(l,r);
00049 return result;
00050 }
00051
00052 void CManhattanWordDistance::cleanup()
00053 {
00054 }
00055
00056 bool CManhattanWordDistance::load_init(FILE* src)
00057 {
00058 return false;
00059 }
00060
00061 bool CManhattanWordDistance::save_init(FILE* dest)
00062 {
00063 return false;
00064 }
00065
00066 DREAL CManhattanWordDistance::compute(INT idx_a, INT idx_b)
00067 {
00068 INT alen, blen;
00069
00070 WORD* avec=((CStringFeatures<WORD>*) lhs)->get_feature_vector(idx_a, alen);
00071 WORD* bvec=((CStringFeatures<WORD>*) rhs)->get_feature_vector(idx_b, blen);
00072
00073 INT result=0;
00074
00075 INT left_idx=0;
00076 INT right_idx=0;
00077
00078 while (left_idx < alen && right_idx < blen)
00079 {
00080 WORD sym=avec[left_idx];
00081 if (avec[left_idx]==bvec[right_idx])
00082 {
00083 INT old_left_idx=left_idx;
00084 INT old_right_idx=right_idx;
00085
00086 while (left_idx< alen && avec[left_idx]==sym)
00087 left_idx++;
00088
00089 while (right_idx< blen && bvec[right_idx]==sym)
00090 right_idx++;
00091
00092 result += CMath::abs( (left_idx-old_left_idx) - (right_idx-old_right_idx) );
00093 }
00094 else if (avec[left_idx]<bvec[right_idx])
00095 {
00096
00097 while (left_idx< alen && avec[left_idx]==sym)
00098 {
00099 result++;
00100 left_idx++;
00101 }
00102 }
00103 else
00104 {
00105 sym=bvec[right_idx];
00106
00107 while (right_idx< blen && bvec[right_idx]==sym)
00108 {
00109 result++;
00110 right_idx++;
00111 }
00112 }
00113 }
00114
00115 result+=blen-right_idx + alen-left_idx;
00116
00117 return result;
00118 }
00119