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 Soeren Sonnenburg 00008 * Copyright (C) 2008-2009 Fraunhofer Institute FIRST and Max-Planck-Society 00009 */ 00010 00011 #include <shogun/lib/common.h> 00012 #include <shogun/kernel/GaussianShortRealKernel.h> 00013 #include <shogun/features/Features.h> 00014 #include <shogun/features/SimpleFeatures.h> 00015 #include <shogun/io/SGIO.h> 00016 00017 using namespace shogun; 00018 00019 CGaussianShortRealKernel::CGaussianShortRealKernel() 00020 : CDotKernel(0), width(0.0) 00021 { 00022 register_params(); 00023 } 00024 00025 CGaussianShortRealKernel::CGaussianShortRealKernel(int32_t size, float64_t w) 00026 : CDotKernel(size), width(w) 00027 { 00028 register_params(); 00029 } 00030 00031 CGaussianShortRealKernel::CGaussianShortRealKernel( 00032 CSimpleFeatures<float32_t>* l, CSimpleFeatures<float32_t>* r, float64_t w, int32_t size) 00033 : CDotKernel(size), width(w) 00034 { 00035 init(l,r); 00036 register_params(); 00037 } 00038 00039 CGaussianShortRealKernel::~CGaussianShortRealKernel() 00040 { 00041 } 00042 00043 bool CGaussianShortRealKernel::init(CFeatures* l, CFeatures* r) 00044 { 00045 CDotKernel::init(l, r); 00046 return init_normalizer(); 00047 } 00048 00049 float64_t CGaussianShortRealKernel::compute(int32_t idx_a, int32_t idx_b) 00050 { 00051 int32_t alen, blen; 00052 bool afree, bfree; 00053 00054 float32_t* avec=((CSimpleFeatures<float32_t>*) lhs)->get_feature_vector(idx_a, alen, afree); 00055 float32_t* bvec=((CSimpleFeatures<float32_t>*) rhs)->get_feature_vector(idx_b, blen, bfree); 00056 ASSERT(alen==blen); 00057 00058 float64_t result=0; 00059 for (int32_t i=0; i<alen; i++) 00060 result+=CMath::sq(avec[i]-bvec[i]); 00061 00062 result=exp(-result/width); 00063 00064 ((CSimpleFeatures<float32_t>*) lhs)->free_feature_vector(avec, idx_a, afree); 00065 ((CSimpleFeatures<float32_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree); 00066 00067 return result; 00068 } 00069 00070 void CGaussianShortRealKernel::register_params() 00071 { 00072 m_parameters->add(&width, "width", "kernel width"); 00073 }