source: trunk/yat/statistics/AUC.h @ 821

Last change on this file since 821 was 821, checked in by Peter, 15 years ago

Modified ROC class to use AUC class in calculation of ROC area. Refs #101

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File size: 3.3 KB
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1#ifndef _theplu_yat_statistics_auc_
2#define _theplu_yat_statistics_auc_
3
4// $Id: AUC.h 821 2007-03-18 16:00:05Z peter $
5
6/*
7  Copyright (C) The authors contributing to this file.
8
9  This file is part of the yat library, http://lev.thep.lu.se/trac/yat
10
11  The yat library is free software; you can redistribute it and/or
12  modify it under the terms of the GNU General Public License as
13  published by the Free Software Foundation; either version 2 of the
14  License, or (at your option) any later version.
15
16  The yat library is distributed in the hope that it will be useful,
17  but WITHOUT ANY WARRANTY; without even the implied warranty of
18  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19  General Public License for more details.
20
21  You should have received a copy of the GNU General Public License
22  along with this program; if not, write to the Free Software
23  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
24  02111-1307, USA.
25*/
26
27#include "Score.h"
28#include "yat/utility/stl_utility.h"
29
30#include <utility>
31#include <map>
32
33namespace theplu {
34namespace yat {
35namespace classifier {
36  class Target;
37}
38namespace utility {
39  class vector;
40}
41namespace statistics { 
42
43  ///
44  /// @brief Class calculating Area Under ROC Curve
45  ///   
46  class AUC : public Score
47  {
48 
49  public:
50    ///
51    ///
52    ///
53    AUC(bool absolute=true);
54
55    /// Function taking \a value, \a target (+1 or -1) and vector
56    /// defining what samples to use. The score is equivalent to
57    /// Mann-Whitney statistics.
58    /// @return the area under the ROC curve. If the area is less
59    /// than 0.5 and absolute=true, 1-area is returned. Complexity is
60    /// \f$ N\log N \f$ where \f$ N \f$ is number of samples.
61    ///
62    double score(const classifier::Target& target, 
63                 const utility::vector& value) const; 
64   
65    /**
66        Function taking values, target, weight and a vector defining
67        what samples to use. The area is defines as \f$ \frac{\sum
68        w^+w^-}{\sum w^+w^-}\f$, where the sum in the numerator goes
69        over all pairs where value+ is larger than value-. The
70        denominator goes over all pairs. If target is equal to 1,
71        sample belonges to class + otherwise sample belongs to class
72        -. @return wheighted version of area under the ROC curve. If
73        the area is less than 0.5 and absolute=true, 1-area is
74        returned. Complexity is \f$ N^2 \f$ where \f$ N \f$ is number
75        of samples.
76    */
77    double score(const classifier::Target& target, 
78                 const classifier::DataLookupWeighted1D& value) const; 
79
80    /**
81        Function taking values, target, weight and a vector defining
82        what samples to use. The area is defines as \f$ \frac{\sum
83        w^+w^-}{\sum w^+w^-}\f$, where the sum in the numerator goes
84        over all pairs where value+ is larger than value-. The
85        denominator goes over all pairs. If target is equal to 1,
86        sample belonges to class + otherwise sample belongs to class
87        -. @return wheighted version of area under the ROC curve. If
88        the area is less than 0.5 and absolute=true, 1-area is
89        returned. Complexity is \f$ N^2 \f$ where \f$ N \f$ is number
90        of samples.
91    */
92    double score(const classifier::Target& target, 
93                 const utility::vector& value, 
94                 const utility::vector& weight) const; 
95
96  private:
97    friend class ROC;
98
99    typedef std::multimap<double, std::pair<bool, double> > MultiMap;
100    double score(const MultiMap&) const;
101   
102  };
103
104}}} // of namespace statistics, yat, and theplu
105
106#endif
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