include/dai/daialg.h

   1 /*  Copyright (C) 2006-2008  Joris Mooij  [j dot mooij at science dot ru dot nl]
   2     Radboud University Nijmegen, The Netherlands
   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 #ifndef __defined_libdai_daialg_h
  23 #define __defined_libdai_daialg_h
  24
  25
  26 #include <string>
  27 #include <iostream>
  28 #include <vector>
  29 #include <dai/factorgraph.h>
  30 #include <dai/regiongraph.h>
  31
  32
  33 namespace dai {
  34
  35
  36 /// The InfAlg class is the common denominator of the various approximate inference algorithms.
  37 /// A InfAlg object represents a discrete factorized probability distribution over multiple variables
  38 /// together with an inference algorithm.
  39 class InfAlg {
  40     public:
  41         /// Clone (virtual copy constructor)
  42         virtual InfAlg* clone() const = 0;
  43
  44         /// Virtual desctructor
  45         // (this is needed because this class contains virtual functions)
  46         virtual ~InfAlg() {}
  47
  48         /// Identifies itself for logging purposes
  49         virtual std::string identify() const = 0;
  50
  51         /// Get single node belief
  52         virtual Factor belief( const Var &n ) const = 0;
  53
  54         /// Get general belief
  55         virtual Factor belief( const VarSet &n ) const = 0;
  56
  57         /// Get all beliefs
  58         virtual std::vector<Factor> beliefs() const = 0;
  59
  60         /// Get log partition sum
  61         virtual Real logZ() const = 0;
  62
  63         /// Clear messages and beliefs
  64         virtual void init() = 0;
  65
  66         /// The actual approximate inference algorithm
  67         virtual double run() = 0;
  68
  69         /// Save factor I
  70         virtual void backupFactor( size_t I ) = 0;
  71         /// Save Factors involving ns
  72         virtual void backupFactors( const VarSet &ns ) = 0;
  73
  74         /// Restore factor I
  75         virtual void restoreFactor( size_t I ) = 0;
  76         /// Restore Factors involving ns
  77         virtual void restoreFactors( const VarSet &ns ) = 0;
  78
  79         /// Clamp variable n to value i (i.e. multiply with a Kronecker delta \f$\delta_{x_n, i}\f$)
  80         virtual void clamp( const Var & n, size_t i ) = 0;
  81
  82         /// Set all factors interacting with var(i) to 1
  83         virtual void makeCavity( size_t i ) = 0;
  84
  85         /// Get reference to underlying FactorGraph
  86         virtual FactorGraph &fg() = 0;
  87
  88         /// Get const reference to underlying FactorGraph
  89         virtual const FactorGraph &fg() const = 0;
  90
  91         /// Return maximum difference between beliefs in the last pass
  92         virtual double maxDiff() const = 0;
  93 };
  94
  95
  96 template <class T>
  97 class DAIAlg : public InfAlg, public T {
  98     public:
  99         /// Default constructor
 100         DAIAlg() : InfAlg(), T() {}
 101
 102         /// Construct from T
 103         DAIAlg( const T &t ) : InfAlg(), T(t) {}
 104
 105         /// Copy constructor
 106         DAIAlg( const DAIAlg & x ) : InfAlg(x), T(x) {}
 107
 108         /// Save factor I (using T::backupFactor)
 109         void backupFactor( size_t I ) { T::backupFactor( I ); }
 110         /// Save Factors involving ns (using T::backupFactors)
 111         void backupFactors( const VarSet &ns ) { T::backupFactors( ns ); }
 112
 113         /// Restore factor I (using T::restoreFactor)
 114         void restoreFactor( size_t I ) { T::restoreFactor( I ); }
 115         /// Restore Factors involving ns (using T::restoreFactors)
 116         void restoreFactors( const VarSet &ns ) { T::restoreFactors( ns ); }
 117
 118         /// Clamp variable n to value i (i.e. multiply with a Kronecker delta \f$\delta_{x_n, i}\f$) (using T::clamp)
 119         void clamp( const Var & n, size_t i ) { T::clamp( n, i ); }
 120
 121         /// Set all factors interacting with var(i) to 1 (using T::makeCavity)
 122         void makeCavity( size_t i ) { T::makeCavity( i ); }
 123
 124         /// Get reference to underlying FactorGraph
 125         FactorGraph &fg() { return (FactorGraph &)(*this); }
 126
 127         /// Get const reference to underlying FactorGraph
 128         const FactorGraph &fg() const { return (const FactorGraph &)(*this); }
 129 };
 130
 131
 132 typedef DAIAlg<FactorGraph> DAIAlgFG;
 133 typedef DAIAlg<RegionGraph> DAIAlgRG;
 134
 135
 136 /// Calculate the marginal of obj on ns by clamping
 137 /// all variables in ns and calculating logZ for each joined state
 138 Factor calcMarginal( const InfAlg & obj, const VarSet & ns, bool reInit );
 139
 140
 141 /// Calculate beliefs of all pairs in ns (by clamping
 142 /// nodes in ns and calculating logZ and the beliefs for each state)
 143 std::vector<Factor> calcPairBeliefs( const InfAlg & obj, const VarSet& ns, bool reInit );
 144
 145
 146 /// Calculate beliefs of all pairs in ns (by clamping
 147 /// pairs in ns and calculating logZ for each joined state)
 148 std::vector<Factor> calcPairBeliefsNew( const InfAlg & obj, const VarSet& ns, bool reInit );
 149
 150
 151 /// Calculate 2nd order interactions of the marginal of obj on ns
 152 Factor calcMarginal2ndO( const InfAlg & obj, const VarSet& ns, bool reInit );
 153
 154
 155 } // end of namespace dai
 156
 157
 158 #endif