include/dai/gibbs.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) 2008  Frederik Eaton  [frederik at ofb dot net]
   8  */
   9
  10
  11 /// \file
  12 /// \brief Defines class Gibbs
  13 /// \todo Improve documentation
  14
  15
  16 #ifndef __defined_libdai_gibbs_h
  17 #define __defined_libdai_gibbs_h
  18
  19
  20 #include <dai/daialg.h>
  21 #include <dai/factorgraph.h>
  22 #include <dai/properties.h>
  23
  24
  25 namespace dai {
  26
  27
  28 /// Approximate inference algorithm "Gibbs sampling"
  29 class Gibbs : public DAIAlgFG {
  30     private:
  31         typedef std::vector<size_t> _count_t;
  32         typedef std::vector<size_t> _state_t;
  33
  34         size_t _sample_count;
  35         std::vector<_count_t> _var_counts;
  36         std::vector<_count_t> _factor_counts;
  37         _state_t _state;
  38
  39     public:
  40         /// Parameters of this inference algorithm
  41         struct Properties {
  42             /// Number of iterations
  43             size_t iters;
  44
  45             /// Verbosity
  46             size_t verbose;
  47         } props;
  48
  49         /// Name of this inference algorithm
  50         static const char *Name;
  51
  52     public:
  53         /// Default constructor
  54         Gibbs() : DAIAlgFG(), _sample_count(0), _var_counts(), _factor_counts(), _state() {}
  55
  56         /// Construct from FactorGraph fg and PropertySet opts
  57         Gibbs( const FactorGraph &fg, const PropertySet &opts ) : DAIAlgFG(fg), _sample_count(0), _var_counts(), _factor_counts(), _state() {
  58             setProperties( opts );
  59             construct();
  60         }
  61
  62
  63         /// @name General InfAlg interface
  64         //@{
  65         virtual Gibbs* clone() const { return new Gibbs(*this); }
  66         virtual std::string identify() const { return std::string(Name) + printProperties(); }
  67         virtual Factor belief( const Var &n ) const;
  68         virtual Factor belief( const VarSet &ns ) const;
  69         virtual std::vector<Factor> beliefs() const;
  70         virtual Real logZ() const { DAI_THROW(NOT_IMPLEMENTED); return 0.0; }
  71         virtual void init();
  72         virtual void init( const VarSet &/*ns*/ ) { init(); }
  73         virtual double run();
  74         virtual double maxDiff() const { DAI_THROW(NOT_IMPLEMENTED); return 0.0; }
  75         virtual size_t Iterations() const { return props.iters; }
  76         //@}
  77
  78
  79         /// @name Additional interface specific for Gibbs
  80         //@{
  81         Factor beliefV( size_t i ) const;
  82         Factor beliefF( size_t I ) const;
  83         void randomizeState();
  84         //@}
  85
  86         /// Return reference to current state vector
  87         std::vector<size_t>& state() { return _state; }
  88
  89         /// Return const reference to current state vector
  90         const std::vector<size_t>& state() const { return _state; }
  91
  92     private:
  93         void updateCounts();
  94         Prob getVarDist( size_t i );
  95         void resampleVar( size_t i );
  96         size_t getFactorEntry( size_t I );
  97         size_t getFactorEntryDiff( size_t I, size_t i );
  98
  99         void construct();
 100         /// Set Props according to the PropertySet opts, where the values can be stored as std::strings or as the type of the corresponding Props member
 101         void setProperties( const PropertySet &opts );
 102         PropertySet getProperties() const;
 103         std::string printProperties() const;
 104 };
 105
 106
 107 } // end of namespace dai
 108
 109
 110 #endif