MinkowskiMetric.cpp

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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/MinkowskiMetric.h"
00015 #include "features/Features.h"
00016 #include "features/SimpleFeatures.h"
00017 
00018 using namespace shogun;
00019 
00020 CMinkowskiMetric::CMinkowskiMetric(float64_t k_)
00021 : CSimpleDistance<float64_t>(), k(k_)
00022 {
00023 }
00024 
00025 CMinkowskiMetric::CMinkowskiMetric(
00026     CSimpleFeatures<float64_t>* l, CSimpleFeatures<float64_t>* r, float64_t k_)
00027 : CSimpleDistance<float64_t>(), k(k_)
00028 {
00029     init(l, r);
00030 }
00031 
00032 CMinkowskiMetric::~CMinkowskiMetric()
00033 {
00034     cleanup();
00035 }
00036 
00037 bool CMinkowskiMetric::init(CFeatures* l, CFeatures* r)
00038 {
00039     bool result=CSimpleDistance<float64_t>::init(l,r);
00040 
00041     return result;
00042 }
00043 
00044 void CMinkowskiMetric::cleanup()
00045 {
00046 }
00047 
00048 float64_t CMinkowskiMetric::compute(int32_t idx_a, int32_t idx_b)
00049 {
00050     int32_t alen, blen;
00051     bool afree, bfree;
00052 
00053     float64_t* avec=
00054         ((CSimpleFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree);
00055     float64_t* bvec=
00056         ((CSimpleFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree);
00057 
00058     ASSERT(avec);
00059     ASSERT(bvec);
00060     ASSERT(alen==blen);
00061 
00062     float64_t absTmp = 0;
00063     float64_t result=0;
00064     {
00065         for (int32_t i=0; i<alen; i++)
00066         {
00067             absTmp=fabs(avec[i]-bvec[i]);
00068             result+=pow(absTmp,k);
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     return pow(result,1/k);
00077 }

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