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00011 #include <shogun/kernel/LogKernel.h>
00012 #include <shogun/mathematics/Math.h>
00013
00014 using namespace shogun;
00015
00016 CLogKernel::CLogKernel(): CKernel(0), m_distance(NULL), m_degree(1.8)
00017 {
00018 init();
00019 }
00020
00021 CLogKernel::CLogKernel(int32_t cache, float64_t degree, CDistance* dist)
00022 : CKernel(cache), m_distance(dist), m_degree(degree)
00023 {
00024 init();
00025 ASSERT(m_distance);
00026 SG_REF(m_distance);
00027 }
00028
00029 CLogKernel::CLogKernel(CFeatures *l, CFeatures *r, float64_t degree, CDistance* dist)
00030 : CKernel(10), m_distance(dist), m_degree(degree)
00031 {
00032 init();
00033 ASSERT(m_distance);
00034 SG_REF(m_distance);
00035 init(l, r);
00036 }
00037
00038 CLogKernel::~CLogKernel()
00039 {
00040 cleanup();
00041 SG_UNREF(m_distance);
00042 }
00043
00044 bool CLogKernel::init(CFeatures* l, CFeatures* r)
00045 {
00046 ASSERT(m_distance);
00047 CKernel::init(l,r);
00048 m_distance->init(l,r);
00049 return init_normalizer();
00050 }
00051
00052 void CLogKernel::init()
00053 {
00054 m_parameters->add(&m_degree, "degree", "Degree kernel parameter.");
00055 m_parameters->add((CSGObject**) &m_distance, "distance", "Distance to be used.");
00056 }
00057
00058 float64_t CLogKernel::compute(int32_t idx_a, int32_t idx_b)
00059 {
00060 float64_t dist = m_distance->distance(idx_a, idx_b);
00061 float64_t temp = pow(dist, m_degree);
00062 temp = log(temp + 1);
00063 return -temp;
00064 }