SimpleAssigner.java

/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    SimpleAssigner.java
 *    Simple (in-order) assignment for K-Means
 *    Copyright (C) 2004 Misha Bilenko, Sugato Basu
 *
 */

package weka.clusterers.assigners; 

import  java.io.*;
import  java.util.*;
import  weka.core.*;
import  weka.clusterers.*;


public class SimpleAssigner extends MPCKMeansAssigner {
  /** Move points in assignment step till stabilization? */
  protected boolean m_MovePointsTillAssignmentStabilizes = false;
  
  /** Number of times points are moved in assignment step till stabilization */
  protected int m_MaxTimesPointsMoved = 100;

  /** Default constructors */
  public SimpleAssigner() {
    super();
  } 

  /** Initialize with a clusterer */
  public SimpleAssigner (MPCKMeans clusterer) {
    super(clusterer);
  }

   /** This is a sequential assignment method */
  public boolean isSequential() {
    return true;
  }

  /** The main method
   *  @return the number of points that changed assignment
   */
  public int assign() throws Exception {
    int moved = 0;
    Instances instances = m_clusterer.getInstances();
    int numInstances = instances.numInstances();

    for (int i=0; i < numInstances; i++) {
      Instance inst = instances.instance(i);
      try { 	// Update number of points moved
	//	System.out.println("Current cluster assignment of " + i + " = " + m_clusterer.getClusterAssignments()[i]);
	moved += m_clusterer.assignInstanceToClusterWithConstraints(i);
      } catch (Exception e) {
	System.out.println("Could not assign instance: " + i + " with current assignment: " + m_clusterer.getClusterAssignments()[i] + ". Exception: " + e);
	e.printStackTrace();
      }
    }

    if (m_MovePointsTillAssignmentStabilizes) {
      int newMoved = -1;
      for (int t=0; t<m_MaxTimesPointsMoved && newMoved != 0; t++) { // move points till assignment stabilizes
	newMoved = 0;

	m_clusterer.resetObjective();
	for (int i = 0; i < numInstances; i++) {
	  newMoved += m_clusterer.assignInstanceToClusterWithConstraints(i);
	}
	if (newMoved > 0) {
	  System.out.println(newMoved + " points moved in t=" + t);
	} else {
	  break; // go out of for loop
	}
      }
    }

    return moved;
  }

  /**
   * Get/Set m_MovePointsTillAssignmentStabilizes
   * @param b truth value
   */
  public void setMovePointsTillAssignmentStabilizes (boolean b) {
    this.m_MovePointsTillAssignmentStabilizes = b;
  }
  public boolean getMovePointsTillAssignmentStabilizes () {
    return  m_MovePointsTillAssignmentStabilizes;
  }

  /** Get/set the number of times points can be moved */
  public int getMaxTimesPointsMoved() {
    return m_MaxTimesPointsMoved;
  }
  public void setMaxTimesPointsMoved(int  v) {
    this.m_MaxTimesPointsMoved = v;
  }

  public void setOptions (String[] options)
    throws Exception {
    // TODO
  }

  public Enumeration listOptions () {
    // TODO
    return null;
  }
  
  public String [] getOptions ()  {
    String[] options = new String[20];
    int current = 0;

    if (m_MovePointsTillAssignmentStabilizes) {
      options[current++] = "-move";
      options[current++] = "" + getMaxTimesPointsMoved();
    }

    while (current < options.length) {
      options[current++] = "";
    }

    return options;
  }
}