source: trunk/yat/classifier/GaussianKernelFunction.cc @ 1706

Last change on this file since 1706 was 1487, checked in by Jari Häkkinen, 13 years ago

Addresses #436. GPL license copy reference should also be updated.

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date ID
File size: 2.6 KB
Line 
1// $Id$
2
3/*
4  Copyright (C) 2004 Jari Häkkinen, Peter Johansson
5  Copyright (C) 2005 Peter Johansson
6  Copyright (C) 2006, 2007 Jari Häkkinen, Peter Johansson
7
8  This file is part of the yat library, http://dev.thep.lu.se/yat
9
10  The yat library is free software; you can redistribute it and/or
11  modify it under the terms of the GNU General Public License as
12  published by the Free Software Foundation; either version 3 of the
13  License, or (at your option) any later version.
14
15  The yat library is distributed in the hope that it will be useful,
16  but WITHOUT ANY WARRANTY; without even the implied warranty of
17  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  General Public License for more details.
19
20  You should have received a copy of the GNU General Public License
21  along with yat. If not, see <http://www.gnu.org/licenses/>.
22*/
23
24#include "GaussianKernelFunction.h"
25#include "KernelFunction.h"
26#include "DataLookup1D.h"
27#include "DataLookupWeighted1D.h"
28
29#include <cassert>
30#include <math.h>
31
32namespace theplu {
33namespace yat {
34namespace classifier { 
35
36  GaussianKernelFunction::GaussianKernelFunction(double sigma) 
37    : KernelFunction(), sigma2_(sigma*sigma)
38  {
39  }
40
41  double GaussianKernelFunction::operator()(const DataLookup1D& x,
42                                            const DataLookup1D& y) const
43  {
44    assert(x.size()==y.size());
45    double d2 = 0;
46    for (size_t i=0; i<x.size(); i++){
47      double d = x(i)-y(i);
48      d2 += d*d;
49    }
50    return exp(-d2/sigma2_); 
51  }
52
53
54  double GaussianKernelFunction::operator()(const DataLookup1D& x,
55                                            const DataLookupWeighted1D& y) const
56  {
57    assert(x.size()==y.size());
58    double d2 = 0;
59    double normalization_factor = 0;
60    for (size_t i=0; i<x.size(); i++) {
61      // ignoring Nan with accompanied weight zero
62      if (y.weight(i)){
63        d2 += y.weight(i) * (x(i)-y.data(i)) * (x(i)-y.data(i));
64        normalization_factor += y.weight(i);
65      }
66    }
67    // to make it coherent with no weight case
68    normalization_factor /= x.size(); 
69    return exp(d2/normalization_factor/sigma2_);
70  }
71
72
73  double GaussianKernelFunction::operator()(const DataLookupWeighted1D& x,
74                                            const DataLookupWeighted1D& y) const
75  {
76    assert(x.size()==y.size());
77    double d2 = 0;
78    double normalization_factor = 0;
79    for (size_t i=0; i<x.size(); i++) {
80      // ignoring Nan with accompanied weight zero
81      if (x.weight(i) && y.weight(i)){
82        d2 += x.weight(i) * y.weight(i) * (x.data(i)-y.data(i)) * 
83          (x.data(i)-y.data(i));
84        normalization_factor += x.weight(i) * y.weight(i);
85      }
86    }
87    // to make it coherent with no weight case
88    normalization_factor /= x.size(); 
89    return exp(d2/normalization_factor/sigma2_);
90  }
91
92
93}}} // of namespace svn, yat, and theplu
Note: See TracBrowser for help on using the repository browser.