include/dai/evidence.h

   1 /*  This file is part of libDAI - http://www.libdai.org/
   2  *
   3  *  libDAI is licensed under the terms of the GNU General Public License version
   4  *  2, or (at your option) any later version. libDAI is distributed without any
   5  *  warranty. See the file COPYING for more details.
   6  *
   7  *  Copyright (C) 2009  Charles Vaske  [cvaske at soe dot ucsc dot edu]
   8  *  Copyright (C) 2009  University of California, Santa Cruz
   9  */
  10
  11
  12 /// \file
  13 /** \brief Defines classes Evidence and Observation
  14  *  \todo Describe tabular data file format
  15  *  \todo Improve documentation
  16  *  \author Charles Vaske
  17  */
  18
  19
  20 #ifndef __defined_libdai_evidence_h
  21 #define __defined_libdai_evidence_h
  22
  23
  24 #include <istream>
  25 #include <dai/daialg.h>
  26
  27
  28 namespace dai {
  29
  30
  31 /// Stores observed values of a subset of variables
  32 /** \author Charles Vaske
  33  */
  34 class Observation {
  35     private:
  36         /// Used to store the state of some variables
  37         std::map<Var, size_t> _obs;
  38
  39     public:
  40         /// Default constructor
  41         Observation() : _obs() {}
  42
  43         /// Get all observations
  44         const std::map<Var, size_t>& observations() const { return _obs; }
  45
  46         /// Add an observation
  47         void addObservation( Var node, size_t setting );
  48
  49         /// Clamp variables in the graphical model to their observed values
  50         void applyEvidence( InfAlg& alg ) const;
  51 };
  52
  53
  54 /// Stores multiple joint observations of sets of variables.
  55 /** The Evidence class stores multiple samples, where each sample is the joint
  56  *  observation of the states of some variables.
  57  *
  58  *  \author Charles Vaske
  59  */
  60 class Evidence {
  61     private:
  62         /// Each sample is the joint observation of the states of some variables
  63         std::vector<Observation> _samples;
  64
  65     public:
  66         /// Default constructor
  67         Evidence() : _samples() {}
  68
  69         /// Construct from existing samples
  70         Evidence( std::vector<Observation> &samples ) : _samples(samples) {}
  71
  72         /// Read in tabular data from a stream.
  73         /** Each line contains one sample, and the first line is a header line with names.
  74          */
  75         void addEvidenceTabFile( std::istream& is, std::map<std::string, Var> &varMap );
  76
  77         /// Read in tabular data from a stream.
  78         /** Each line contains one sample, and the first line is a header line with
  79          *  variable labels which should correspond with a subset of the variables in fg.
  80          */
  81         void addEvidenceTabFile( std::istream& is, FactorGraph& fg );
  82
  83         /// Returns number of stored samples
  84         size_t nrSamples() const { return _samples.size(); }
  85
  86     /// \name Iterator interface
  87     //@{
  88         /// Iterator over the elements
  89         typedef std::vector<Observation>::iterator iterator;
  90         /// Constant iterator over the elements
  91         typedef std::vector<Observation>::const_iterator const_iterator;
  92
  93         /// Returns iterator that points to the first element
  94         iterator begin() { return _samples.begin(); }
  95         /// Returns constant iterator that points to the first element
  96         const_iterator begin() const { return _samples.begin(); }
  97         /// Returns iterator that points beyond the last element
  98         iterator end() { return _samples.end(); }
  99         /// Returns constant iterator that points beyond the last element
 100         const_iterator end() const { return _samples.end(); }
 101     //@}
 102 };
 103
 104
 105 } // end of namespace dai
 106
 107
 108 #endif