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LogKernel.cpp
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1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License as published by
4  * the Free Software Foundation; either version 3 of the License, or
5  * (at your option) any later version.
6  *
7  * Written (W) 2011 Jakub Jirku
8  * Copyright (C) 2007-2011 Fraunhofer Institute FIRST and Max-Planck-Society
9  */
10 
13 
14 using namespace shogun;
15 
16 CLogKernel::CLogKernel(): CKernel(0), m_distance(NULL), m_degree(1.8)
17 {
18  init();
19 }
20 
21 CLogKernel::CLogKernel(int32_t cache, float64_t degree, CDistance* dist)
22 : CKernel(cache), m_distance(dist), m_degree(degree)
23 {
24  init();
27 }
28 
30 : CKernel(10), m_distance(dist), m_degree(degree)
31 {
32  init();
35  init(l, r);
36 }
37 
39 {
40  cleanup();
42 }
43 
44 bool CLogKernel::init(CFeatures* l, CFeatures* r)
45 {
47  CKernel::init(l,r);
48  m_distance->init(l,r);
49  return init_normalizer();
50 }
51 
52 void CLogKernel::init()
53 {
54  SG_ADD(&m_degree, "degree", "Degree kernel parameter.", MS_AVAILABLE);
55  SG_ADD((CSGObject**) &m_distance, "distance", "Distance to be used.",
56  MS_AVAILABLE);
57 }
58 
59 float64_t CLogKernel::compute(int32_t idx_a, int32_t idx_b)
60 {
61  float64_t dist = m_distance->distance(idx_a, idx_b);
62  float64_t temp = pow(dist, m_degree);
63  temp = log(temp + 1);
64  return -temp;
65 }

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