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 void MF::setProperties( const PropertySet &opts ) {
  41     assert( opts.hasKey("tol") );
  42     assert( opts.hasKey("maxiter") );
  43     assert( opts.hasKey("verbose") );
  44
  45     props.tol = opts.getStringAs<double>("tol");
  46     props.maxiter = opts.getStringAs<size_t>("maxiter");
  47     props.verbose = opts.getStringAs<size_t>("verbose");
  48 }
  49
  50
  51 PropertySet MF::getProperties() const {
  52     PropertySet opts;
  53     opts.Set( "tol", props.tol );
  54     opts.Set( "maxiter", props.maxiter );
  55     opts.Set( "verbose", props.verbose );
  56     return opts;
  57 }
  58
  59
  60 void MF::create() {
  61     // clear beliefs
  62     _beliefs.clear();
  63     _beliefs.reserve( nrVars() );
  64
  65     // create beliefs
  66     for( size_t i = 0; i < nrVars(); ++i )
  67         _beliefs.push_back(Factor(var(i)));
  68 }
  69
  70
  71 string MF::identify() const {
  72     stringstream result (stringstream::out);
  73     result << Name << getProperties();
  74     return result.str();
  75 }
  76
  77
  78 void MF::init() {
  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     double tic = toc();
  86
  87     if( props.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 < (props.maxiter*pass_size) && diffs.maxDiff() > props.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     if( diffs.maxDiff() > maxdiff )
 125         maxdiff = diffs.maxDiff();
 126
 127     if( props.verbose >= 1 ) {
 128         if( diffs.maxDiff() > props.tol ) {
 129             if( props.verbose == 1 )
 130                 cout << endl;
 131             cout << "MF::run:  WARNING: not converged within " << props.maxiter << " passes (" << toc() - tic << " clocks)...final maxdiff:" << diffs.maxDiff() << endl;
 132         } else {
 133             if( props.verbose >= 2 )
 134                 cout << "MF::run:  ";
 135             cout << "converged in " << t / pass_size << " passes (" << toc() - tic << " clocks)." << endl;
 136         }
 137     }
 138
 139     return diffs.maxDiff();
 140 }
 141
 142
 143 Factor MF::beliefV (size_t i) const {
 144     Factor piet;
 145     piet = _beliefs[i];
 146     piet.normalize( Prob::NORMPROB );
 147     return(piet);
 148 }
 149
 150
 151 Factor MF::belief (const VarSet &ns) const {
 152     if( ns.size() == 1 )
 153         return belief( *(ns.begin()) );
 154     else {
 155         assert( ns.size() == 1 );
 156         return Factor();
 157     }
 158 }
 159
 160
 161 Factor MF::belief (const Var &n) const {
 162     return( beliefV( findVar( n ) ) );
 163 }
 164
 165
 166 vector<Factor> MF::beliefs() const {
 167     vector<Factor> result;
 168     for( size_t i = 0; i < nrVars(); i++ )
 169         result.push_back( beliefV(i) );
 170     return result;
 171 }
 172
 173
 174 Complex MF::logZ() const {
 175     Complex sum = 0.0;
 176
 177     for(size_t i=0; i < nrVars(); i++ )
 178         sum -= beliefV(i).entropy();
 179     for(size_t I=0; I < nrFactors(); I++ ) {
 180         Factor henk;
 181         foreach( const Neighbor &j, nbF(I) )  // for all j in I
 182             henk *= _beliefs[j];
 183         henk.normalize( Prob::NORMPROB );
 184         Factor piet;
 185         piet = factor(I).log0();
 186         piet *= henk;
 187         sum -= Complex( piet.totalSum() );
 188     }
 189
 190     return -sum;
 191 }
 192
 193
 194 void MF::init( const VarSet &ns ) {
 195     for( size_t i = 0; i < nrVars(); i++ ) {
 196         if( ns.contains(var(i) ) )
 197             _beliefs[i].fill( 1.0 );
 198     }
 199 }
 200
 201
 202 } // end of namespace dai