src/mf.cpp

   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 #include <iostream>
  23 #include <sstream>
  24 #include <map>
  25 #include <set>
  26 #include <dai/mf.h>
  27 #include <dai/diffs.h>
  28 #include <dai/util.h>
  29
  30
  31 namespace dai {
  32
  33
  34 using namespace std;
  35
  36
  37 const char *MF::Name = "MF";
  38
  39
  40 bool MF::checkProperties() {
  41     if( !HasProperty("tol") )
  42         return false;
  43     if (!HasProperty("maxiter") )
  44         return false;
  45     if (!HasProperty("verbose") )
  46         return false;
  47
  48     ConvertPropertyTo<double>("tol");
  49     ConvertPropertyTo<size_t>("maxiter");
  50     ConvertPropertyTo<size_t>("verbose");
  51
  52     return true;
  53 }
  54
  55
  56 void MF::Regenerate() {
  57 //    DAIAlgFG::Regenerate();
  58
  59     // clear beliefs
  60     _beliefs.clear();
  61     _beliefs.reserve( nrVars() );
  62
  63     // create beliefs
  64     for( size_t i = 0; i < nrVars(); ++i )
  65         _beliefs.push_back(Factor(var(i)));
  66 }
  67
  68
  69 string MF::identify() const {
  70     stringstream result (stringstream::out);
  71     result << Name << GetProperties();
  72     return result.str();
  73 }
  74
  75
  76 void MF::init() {
  77     assert( checkProperties() );
  78
  79     for( vector<Factor>::iterator qi = _beliefs.begin(); qi != _beliefs.end(); qi++ )
  80         qi->fill(1.0);
  81 }
  82
  83
  84 double MF::run() {
  85     clock_t tic = toc();
  86
  87     if( Verbose() >= 1 )
  88         cout << "Starting " << identify() << "...";
  89
  90     size_t pass_size = _beliefs.size();
  91     Diffs diffs(pass_size * 3, 1.0);
  92
  93     size_t t=0;
  94     for( t=0; t < (MaxIter()*pass_size) && diffs.max() > Tol(); t++ ) {
  95         // choose random Var i
  96         size_t i = (size_t) (nrVars() * rnd_uniform());
  97
  98         Factor jan;
  99         Factor piet;
 100         foreach( const Neighbor &I, nbV(i) ) {
 101             Factor henk;
 102             foreach( const Neighbor &j, nbF(I) ) // for all j in I \ i
 103                 if( j != i )
 104                     henk *= _beliefs[j];
 105             piet = factor(I).log0();
 106             piet *= henk;
 107             piet = piet.part_sum(var(i));
 108             piet = piet.exp();
 109             jan *= piet;
 110         }
 111
 112         jan.normalize( _normtype );
 113
 114         if( jan.hasNaNs() ) {
 115             cout << "MF::run():  ERROR: jan has NaNs!" << endl;
 116             return NAN;
 117         }
 118
 119         diffs.push( dist( jan, _beliefs[i], Prob::DISTLINF ) );
 120
 121         _beliefs[i] = jan;
 122     }
 123
 124     updateMaxDiff( diffs.max() );
 125
 126     if( Verbose() >= 1 ) {
 127         if( diffs.max() > Tol() ) {
 128             if( Verbose() == 1 )
 129                 cout << endl;
 130             cout << "MF::run:  WARNING: not converged within " << MaxIter() << " passes (" << toc() - tic << " clocks)...final maxdiff:" << diffs.max() << endl;
 131         } else {
 132             if( Verbose() >= 2 )
 133                 cout << "MF::run:  ";
 134             cout << "converged in " << t / pass_size << " passes (" << toc() - tic << " clocks)." << endl;
 135         }
 136     }
 137
 138     return diffs.max();
 139 }
 140
 141
 142 Factor MF::beliefV (size_t i) const {
 143     Factor piet;
 144     piet = _beliefs[i];
 145     piet.normalize( Prob::NORMPROB );
 146     return(piet);
 147 }
 148
 149
 150 Factor MF::belief (const VarSet &ns) const {
 151     if( ns.size() == 1 )
 152         return belief( *(ns.begin()) );
 153     else {
 154         assert( ns.size() == 1 );
 155         return Factor();
 156     }
 157 }
 158
 159
 160 Factor MF::belief (const Var &n) const {
 161     return( beliefV( findVar( n ) ) );
 162 }
 163
 164
 165 vector<Factor> MF::beliefs() const {
 166     vector<Factor> result;
 167     for( size_t i = 0; i < nrVars(); i++ )
 168         result.push_back( beliefV(i) );
 169     return result;
 170 }
 171
 172
 173 Complex MF::logZ() const {
 174     Complex sum = 0.0;
 175
 176     for(size_t i=0; i < nrVars(); i++ )
 177         sum -= beliefV(i).entropy();
 178     for(size_t I=0; I < nrFactors(); I++ ) {
 179         Factor henk;
 180         foreach( const Neighbor &j, nbF(I) )  // for all j in I
 181             henk *= _beliefs[j];
 182         henk.normalize( Prob::NORMPROB );
 183         Factor piet;
 184         piet = factor(I).log0();
 185         piet *= henk;
 186         sum -= Complex( piet.totalSum() );
 187     }
 188
 189     return -sum;
 190 }
 191
 192
 193 void MF::init( const VarSet &ns ) {
 194     for( size_t i = 0; i < nrVars(); i++ ) {
 195         if( ns && var(i) )
 196             _beliefs[i].fill( 1.0 );
 197     }
 198 }
 199
 200
 201 } // end of namespace dai