SHOGUN v0.9.0
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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) 2006-2009 Christian Gehl 00008 * Copyright (C) 2006-2009 Fraunhofer Institute FIRST 00009 */ 00010 00011 #include "lib/config.h" 00012 #include "lib/common.h" 00013 #include "lib/io.h" 00014 #include "distance/JensenMetric.h" 00015 #include "features/Features.h" 00016 #include "features/SimpleFeatures.h" 00017 00018 using namespace shogun; 00019 00020 CJensenMetric::CJensenMetric() : CSimpleDistance<float64_t>() 00021 { 00022 } 00023 00024 CJensenMetric::CJensenMetric(CSimpleFeatures<float64_t>* l, CSimpleFeatures<float64_t>* r) 00025 : CSimpleDistance<float64_t>() 00026 { 00027 init(l, r); 00028 } 00029 00030 CJensenMetric::~CJensenMetric() 00031 { 00032 cleanup(); 00033 } 00034 00035 bool CJensenMetric::init(CFeatures* l, CFeatures* r) 00036 { 00037 return CSimpleDistance<float64_t>::init(l,r); 00038 } 00039 00040 void CJensenMetric::cleanup() 00041 { 00042 } 00043 00044 float64_t CJensenMetric::compute(int32_t idx_a, int32_t idx_b) 00045 { 00046 int32_t alen, blen; 00047 bool afree, bfree; 00048 00049 float64_t* avec= 00050 ((CSimpleFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree); 00051 float64_t* bvec= 00052 ((CSimpleFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree); 00053 00054 ASSERT(alen==blen); 00055 00056 float64_t absTmp = 0; 00057 float64_t result=0; 00058 { 00059 for (int32_t i=0; i<alen; i++) 00060 { 00061 absTmp=0.5*(avec[i]+bvec[i]); 00062 if (absTmp>0) 00063 { 00064 if(avec[i]>0) 00065 result+=avec[i]*log(avec[i]/absTmp); 00066 if(bvec[i]>0) 00067 result+=bvec[i]*log(bvec[i]/absTmp); 00068 } 00069 } 00070 00071 } 00072 00073 ((CSimpleFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree); 00074 ((CSimpleFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree); 00075 00076 00077 return result; 00078 }