source: trunk/yat/classifier/GaussianKernelFunction.cc @ 781

Last change on this file since 781 was 781, checked in by Peter, 15 years ago

changing name to ROCScore and also added some cassert includes

  • 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) The authors contributing to this file.
5
6  This file is part of the yat library, http://lev.thep.lu.se/trac/yat
7
8  The yat library is free software; you can redistribute it and/or
9  modify it under the terms of the GNU General Public License as
10  published by the Free Software Foundation; either version 2 of the
11  License, or (at your option) any later version.
12
13  The yat library is distributed in the hope that it will be useful,
14  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  General Public License for more details.
17
18  You should have received a copy of the GNU General Public License
19  along with this program; if not, write to the Free Software
20  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
21  02111-1307, USA.
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
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