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
  17
  18 #ifndef __defined_libdai_evidence_h
  19 #define __defined_libdai_evidence_h
  20
  21
  22 #include <istream>
  23 #include <dai/daialg.h>
  24
  25
  26 namespace dai {
  27
  28
  29 /// Stores observed values of a subset of variables
  30 class Observation {
  31     private:
  32         /// Used to store the state of some variables
  33         std::map<Var, size_t> _obs;
  34
  35     public:
  36         /// Default constructor
  37         Observation() : _obs() {}
  38
  39         /// Get all observations
  40         const std::map<Var, size_t>& observations() const { return _obs; }
  41
  42         /// Add an observation
  43         void addObservation( Var node, size_t setting );
  44
  45         /// Clamp variables in the graphical model to their observed values
  46         void applyEvidence( InfAlg& alg ) const;
  47 };
  48
  49
  50 /// Stores multiple joint observations of sets of variables.
  51 /** The Evidence class stores multiple samples, where each sample is the joint
  52  *  observation of the states of some variables.
  53  */
  54 class Evidence {
  55     private:
  56         /// Each sample is the joint observation of the states of some variables
  57         std::vector<Observation> _samples;
  58
  59     public:
  60         /// Default constructor
  61         Evidence() : _samples() {}
  62
  63         /// Construct from existing samples
  64         Evidence( std::vector<Observation> &samples ) : _samples(samples) {}
  65
  66         /// Read in tabular data from a stream.
  67         /** Each line contains one sample, and the first line is a header line with names.
  68          */
  69         void addEvidenceTabFile( std::istream& is, std::map<std::string, Var> &varMap );
  70
  71         /// Read in tabular data from a stream.
  72         /** Each line contains one sample, and the first line is a header line with
  73          *  variable labels which should correspond with a subset of the variables in fg.
  74          */
  75         void addEvidenceTabFile( std::istream& is, FactorGraph& fg );
  76
  77         /// Returns number of stored samples
  78         size_t nrSamples() const { return _samples.size(); }
  79
  80         /// @name Iterator interface
  81         //@{
  82         /// Iterator over the elements
  83         typedef std::vector<Observation>::iterator iterator;
  84         /// Constant iterator over the elements
  85         typedef std::vector<Observation>::const_iterator const_iterator;
  86
  87         /// Returns iterator that points to the first element
  88         iterator begin() { return _samples.begin(); }
  89         /// Returns constant iterator that points to the first element
  90         const_iterator begin() const { return _samples.begin(); }
  91         /// Returns iterator that points beyond the last element
  92         iterator end() { return _samples.end(); }
  93         /// Returns constant iterator that points beyond the last element
  94         const_iterator end() const { return _samples.end(); }
  95         //@}
  96 };
  97
  98
  99 } // end of namespace dai
 100
 101
 102 #endif