SHOGUN
v3.2.0
|
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) 2010 Koen van de Sande 00008 * Copyright (C) 2010 Koen van de Sande / University of Amsterdam 00009 */ 00010 00011 #include <shogun/lib/common.h> 00012 #include <shogun/kernel/HistogramIntersectionKernel.h> 00013 #include <shogun/features/Features.h> 00014 #include <shogun/io/SGIO.h> 00015 00016 using namespace shogun; 00017 00018 CHistogramIntersectionKernel::CHistogramIntersectionKernel() 00019 : CDotKernel(0), m_beta(1.0) 00020 { 00021 register_params(); 00022 } 00023 00024 CHistogramIntersectionKernel::CHistogramIntersectionKernel(int32_t size) 00025 : CDotKernel(size), m_beta(1.0) 00026 { 00027 register_params(); 00028 } 00029 00030 CHistogramIntersectionKernel::CHistogramIntersectionKernel( 00031 CDenseFeatures<float64_t>* l, CDenseFeatures<float64_t>* r, 00032 float64_t beta, int32_t size) 00033 : CDotKernel(size), m_beta(beta) 00034 { 00035 init(l,r); 00036 register_params(); 00037 } 00038 00039 CHistogramIntersectionKernel::~CHistogramIntersectionKernel() 00040 { 00041 cleanup(); 00042 } 00043 00044 bool CHistogramIntersectionKernel::init(CFeatures* l, CFeatures* r) 00045 { 00046 bool result=CDotKernel::init(l,r); 00047 init_normalizer(); 00048 return result; 00049 } 00050 00051 float64_t CHistogramIntersectionKernel::compute(int32_t idx_a, int32_t idx_b) 00052 { 00053 int32_t alen, blen; 00054 bool afree, bfree; 00055 00056 float64_t* avec= 00057 ((CDenseFeatures<float64_t>*) lhs)->get_feature_vector(idx_a, alen, afree); 00058 float64_t* bvec= 00059 ((CDenseFeatures<float64_t>*) rhs)->get_feature_vector(idx_b, blen, bfree); 00060 ASSERT(alen==blen) 00061 00062 float64_t result=0; 00063 00064 // checking if beta is default or not 00065 if (m_beta == 1.0) 00066 { 00067 // compute standard histogram intersection kernel 00068 for (int32_t i=0; i<alen; i++) 00069 result += (avec[i] < bvec[i]) ? avec[i] : bvec[i]; 00070 } 00071 else 00072 { 00073 //compute generalized histogram intersection kernel 00074 for (int32_t i=0; i<alen; i++) 00075 result += CMath::min(CMath::pow(avec[i],m_beta), CMath::pow(bvec[i],m_beta)); 00076 } 00077 ((CDenseFeatures<float64_t>*) lhs)->free_feature_vector(avec, idx_a, afree); 00078 ((CDenseFeatures<float64_t>*) rhs)->free_feature_vector(bvec, idx_b, bfree); 00079 00080 return result; 00081 } 00082 00083 void CHistogramIntersectionKernel::register_params() 00084 { 00085 SG_ADD(&m_beta, "beta", "the beta parameter of the kernel", MS_AVAILABLE); 00086 }