cc.mallet.grmm.inference.gbp.ClusterVariationalRegionGenerator Maven / Gradle / Ivy

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MALLET is a Java-based package for statistical natural language processing, document classification, clustering, topic modeling, information extraction, and other machine learning applications to text.

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/* Copyright (C) 2003 Univ. of Massachusetts Amherst, Computer Science Dept.
   This file is part of "MALLET" (MAchine Learning for LanguagE Toolkit).
   http://www.cs.umass.edu/~mccallum/mallet
   This software is provided under the terms of the Common Public License,
   version 1.0, as published by http://www.opensource.org.  For further
   information, see the file `LICENSE' included with this distribution. */
package cc.mallet.grmm.inference.gbp;


import java.util.*;
import java.util.logging.Logger;

import cc.mallet.grmm.types.Factor;
import cc.mallet.grmm.types.FactorGraph;
import cc.mallet.grmm.types.UndirectedGrid;
import cc.mallet.grmm.types.Variable;
import cc.mallet.util.CollectionUtils;
import cc.mallet.util.MalletLogger;

/**
 * Created: Jun 1, 2005
 *
 * @author = region.vars.size ()) {
          if (r2.vars.containsAll (region.vars)) {
            it.remove ();
            break;
          }
        }
      }
    }
  }

  public static void addAllFactors (FactorGraph mdl, List regions)
  {
    for (Iterator it = regions.iterator (); it.hasNext ();) {
      Region region = (Region) it.next ();
      for (Iterator pIt = mdl.factorsIterator (); pIt.hasNext();) {
        Factor ptl = (Factor) pIt.next ();
        if (region.vars.containsAll (ptl.varSet ())) {
          region.factors.add (ptl);
        }
      }
    }
  }

  public static interface BaseRegionComputer {
    /**
     * Returns a list of top-level regions for use in the cluster variational method.
     * @param mdl An undirected model.
     * @return A list of regions.  No region in the list may subsume another.
     */
    List computeBaseRegions (FactorGraph mdl);
  }

  /**
   * Region computer where each top-level region consists of a single factor node.
   *  If the model is pairwise, this is equivalent to using the Bethe free energy.
   */
  public static class ByFactorRegionComputer implements BaseRegionComputer {

    public List computeBaseRegions (FactorGraph mdl)
    {
      List regions = new ArrayList (mdl.factors ().size ());
      for (Iterator it = mdl.factorsIterator (); it.hasNext ();) {
        Factor ptl =  (Factor) it.next ();
        regions.add (new Region (ptl));
      }
      removeSubsumedRegions (regions);
      addAllFactors (mdl, regions);
      return regions;
    }

  }

  public static class Grid2x2RegionComputer implements BaseRegionComputer {

    public List computeBaseRegions (FactorGraph mdl)
    {
      List regions = new ArrayList ();
      UndirectedGrid grid = (UndirectedGrid) mdl;
      for (int x = 0; x < grid.getWidth() - 1; x++) {
        for (int y = 0; y < grid.getHeight() - 1; y++) {
          Variable[] vars = new Variable[] {
            grid.get (x, y),
            grid.get (x, y+1),
            grid.get (x+1, y+1),
            grid.get (x+1, y),
          };
          regions.add (new Region (vars, new Factor[0]));
        }
      }
      addAllFactors (mdl, regions);
      return regions;
    }
  }

}

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