include/dai/evidence.h

   1 /*  Copyright (C) 2009  Charles Vaske  [cvaske at soe dot ucsc dot edu]
   2     University of California Santa Cruz
   3
   4     This file is part of libDAI.
   5
   6     libDAI is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     libDAI is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with libDAI; if not, write to the Free Software
  18     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 */
  20
  21
  22 /// \file
  23 /// \brief Defines classes Evidence and Observation
  24 /// \todo Describe tabular data file format
  25
  26
  27 #ifndef __defined_libdai_evidence_h
  28 #define __defined_libdai_evidence_h
  29
  30
  31 #include <istream>
  32 #include <dai/daialg.h>
  33
  34
  35 namespace dai {
  36
  37
  38 /// Stores observed values of a subset of variables
  39 class Observation {
  40     private:
  41         /// Used to store the state of some variables
  42         std::map<Var, size_t> _obs;
  43
  44     public:
  45         /// Default constructor
  46         Observation() : _obs() {}
  47
  48         /// Get all observations
  49         const std::map<Var, size_t>& observations() const { return _obs; }
  50
  51         /// Add an observation
  52         void addObservation( Var node, size_t setting );
  53
  54         /// Clamp variables in the graphical model to their observed values
  55         void applyEvidence( InfAlg& alg ) const;
  56 };
  57
  58
  59 /// Stores multiple joint observations of sets of variables.
  60 /** The Evidence class stores multiple samples, where each sample is the joint
  61  *  observation of the states of some variables.
  62  */
  63 class Evidence {
  64     private:
  65         /// Each sample is the joint observation of the states of some variables
  66         std::vector<Observation> _samples;
  67
  68     public:
  69         /// Default constructor
  70         Evidence() : _samples() {}
  71
  72         /// Constructor with existing samples
  73           Evidence(std::vector<Observation>& samples) : _samples(samples) {}
  74
  75 /// Read in tabular data from a stream.
  76         /** Each line contains one sample, and the first line is a header line with names.
  77          */
  78         void addEvidenceTabFile( std::istream& is, std::map<std::string, Var> &varMap );
  79
  80
  81         /// Read in tabular data from a stream.
  82         /** Each line contains one sample, and the first line is a header line with
  83          *  variable labels which should correspond with a subset of the variables in fg.
  84          */
  85         void addEvidenceTabFile( std::istream& is, FactorGraph& fg );
  86
  87         /// Returns number of stored samples
  88         size_t nrSamples() const { return _samples.size(); }
  89
  90         /// @name Iterator interface
  91         //@{
  92         /// Iterator over the elements
  93         typedef std::vector<Observation>::iterator iterator;
  94         /// Constant iterator over the elements
  95         typedef std::vector<Observation>::const_iterator const_iterator;
  96
  97         /// Returns iterator that points to the first element
  98         iterator begin() { return _samples.begin(); }
  99         /// Returns constant iterator that points to the first element
 100         const_iterator begin() const { return _samples.begin(); }
 101         /// Returns iterator that points beyond the last element
 102         iterator end() { return _samples.end(); }
 103         /// Returns constant iterator that points beyond the last element
 104         const_iterator end() const { return _samples.end(); }
 105         //@}
 106 };
 107
 108
 109 } // end of namespace dai
 110
 111
 112 #endif