SHOGUN
v1.1.0
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00001 /* 00002 * This program is free software; you can redistribute it and/or modify 00003 * it under the terms of the GNU General Public License as published by 00004 * the Free Software Foundation; either version 3 of the License, or 00005 * (at your option) any later version. 00006 * 00007 * Written (W) 2008-2009 Christian Gehl 00008 * Copyright (C) 2008-2009 Fraunhofer Institute FIRST 00009 */ 00010 00011 #include <shogun/lib/config.h> 00012 #include <shogun/lib/common.h> 00013 #include <shogun/io/SGIO.h> 00014 #include <shogun/distance/BrayCurtisDistance.h> 00015 #include <shogun/features/Features.h> 00016 #include <shogun/features/SimpleFeatures.h> 00017 00018 using namespace shogun; 00019 00020 CBrayCurtisDistance::CBrayCurtisDistance() 00021 : CSimpleDistance<float64_t>() 00022 { 00023 } 00024 00025 CBrayCurtisDistance::CBrayCurtisDistance(CSimpleFeatures<float64_t>* l, CSimpleFeatures<float64_t>* r) 00026 : CSimpleDistance<float64_t>() 00027 { 00028 init(l, r); 00029 } 00030 00031 CBrayCurtisDistance::~CBrayCurtisDistance() 00032 { 00033 cleanup(); 00034 } 00035 00036 bool CBrayCurtisDistance::init(CFeatures* l, CFeatures* r) 00037 { 00038 bool result=CSimpleDistance<float64_t>::init(l,r); 00039 00040 return result; 00041 } 00042 00043 void CBrayCurtisDistance::cleanup() 00044 { 00045 } 00046 00047 float64_t CBrayCurtisDistance::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 00059 float64_t s1=0; 00060 float64_t s2=0; 00061 { 00062 for (int32_t i=0; i<alen; i++) 00063 { 00064 s1+=fabs(avec[i]-bvec[i]); 00065 s2+=fabs(avec[i]+bvec[i]); 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 // trap division by zero 00073 if(s2==0) 00074 return 0; 00075 00076 return (s1/s2); 00077 }