src/exactinf.cpp

   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) 2006-2009  Joris Mooij  [joris dot mooij at libdai dot org]
   8  *  Copyright (C) 2006-2007  Radboud University Nijmegen, The Netherlands
   9  */
  10
  11
  12 #include <dai/exactinf.h>
  13 #include <sstream>
  14
  15
  16 namespace dai {
  17
  18
  19 using namespace std;
  20
  21
  22 const char *ExactInf::Name = "EXACT";
  23
  24
  25 void ExactInf::setProperties( const PropertySet &opts ) {
  26     assert( opts.hasKey("verbose") );
  27
  28     props.verbose = opts.getStringAs<size_t>("verbose");
  29 }
  30
  31
  32 PropertySet ExactInf::getProperties() const {
  33     PropertySet opts;
  34     opts.Set( "verbose", props.verbose );
  35     return opts;
  36 }
  37
  38
  39 string ExactInf::printProperties() const {
  40     stringstream s( stringstream::out );
  41     s << "[";
  42     s << "verbose=" << props.verbose << "]";
  43     return s.str();
  44 }
  45
  46
  47 void ExactInf::construct() {
  48     // clear variable beliefs and reserve space
  49     _beliefsV.clear();
  50     _beliefsV.reserve( nrVars() );
  51     for( size_t i = 0; i < nrVars(); i++ )
  52         _beliefsV.push_back( Factor( var(i) ) );
  53
  54     // clear factor beliefs and reserve space
  55     _beliefsF.clear();
  56     _beliefsF.reserve( nrFactors() );
  57     for( size_t I = 0; I < nrFactors(); I++ )
  58         _beliefsF.push_back( Factor( factor(I).vars() ) );
  59 }
  60
  61
  62 void ExactInf::init() {
  63     for( size_t i = 0; i < nrVars(); i++ )
  64         _beliefsV[i].fill( 1.0 );
  65     for( size_t I = 0; I < nrFactors(); I++ )
  66         _beliefsF[I].fill( 1.0 );
  67 }
  68
  69
  70 double ExactInf::run() {
  71     if( props.verbose >= 1 )
  72         cerr << "Starting " << identify() << "...";
  73
  74     Factor P;
  75     for( size_t I = 0; I < nrFactors(); I++ )
  76         P *= factor(I);
  77
  78     Real Z = P.sum();
  79     _logZ = std::log(Z);
  80     for( size_t i = 0; i < nrVars(); i++ )
  81         _beliefsV[i] = P.marginal(var(i));
  82     for( size_t I = 0; I < nrFactors(); I++ )
  83         _beliefsF[I] = P.marginal(factor(I).vars());
  84
  85     if( props.verbose >= 1 )
  86         cerr << "finished" << endl;
  87
  88     return 0.0;
  89 }
  90
  91
  92 vector<Factor> ExactInf::beliefs() const {
  93     vector<Factor> result = _beliefsV;
  94     result.insert( result.end(), _beliefsF.begin(), _beliefsF.end() );
  95     return result;
  96 }
  97
  98
  99 Factor ExactInf::belief( const VarSet &ns ) const {
 100     if( ns.size() == 0 )
 101         return Factor();
 102     else if( ns.size() == 1 ) {
 103         return belief( *(ns.begin()) );
 104     } else {
 105         size_t I;
 106         for( I = 0; I < nrFactors(); I++ )
 107             if( factor(I).vars() >> ns )
 108                 break;
 109         assert( I != nrFactors() );
 110         return beliefF(I).marginal(ns);
 111     }
 112 }
 113
 114
 115 string ExactInf::identify() const {
 116     return string(Name) + printProperties();
 117 }
 118
 119
 120 } // end of namespace dai