randomtree.java

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/*
 *    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.
 */

/*
 *    RandomTree.java
 *    Copyright (C) 2001 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.classifiers.trees;

import weka.classifiers.Classifier;
import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.ContingencyTables;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Randomizable;
import weka.core.Utils;
import weka.core.WeightedInstancesHandler;
import weka.core.Capabilities.Capability;

import java.util.Enumeration;
import java.util.Random;
import java.util.Vector;

/**
 <!-- globalinfo-start -->
 * Class for constructing a tree that considers K randomly  chosen attributes at each node. Performs no pruning.
 * <p/>
 <!-- globalinfo-end -->
 *
 <!-- options-start -->
 * Valid options are: <p/>
 * 
 * <pre> -K &lt;number of attributes&gt;
 *  Number of attributes to randomly investigate
 *  (&lt;1 = int(log(#attributes)+1)).</pre>
 * 
 * <pre> -M &lt;minimum number of instances&gt;
 *  Set minimum number of instances per leaf.</pre>
 * 
 * <pre> -S &lt;num&gt;
 *  Seed for random number generator.
 *  (default 1)</pre>
 * 
 * <pre> -depth &lt;num&gt;
 *  The maximum depth of the tree, 0 for unlimited.
 *  (default 0)</pre>
 * 
 * <pre> -D
 *  If set, classifier is run in debug mode and
 *  may output additional info to the console</pre>
 * 
 <!-- options-end -->
 *
 * @author Eibe Frank ([e-mail])
 * @author Richard Kirkby ([e-mail])
 * @version $Revision: 1.19 $
 */
public class RandomTree 
  extends Classifier 
  implements OptionHandler, WeightedInstancesHandler, Randomizable {

  /** for serialization */
  static final long serialVersionUID = 8934314652175299374L;
  
  /** The subtrees appended to this tree. */ 
  protected RandomTree[] m_Successors;
    
  /** The attribute to split on. */
  protected int m_Attribute = -1;
    
  /** The split point. */
  protected double m_SplitPoint = Double.NaN;
    
  /** The class distribution from the training data. */
  protected double[][] m_Distribution = null;
    
  /** The header information. */
  protected Instances m_Info = null;
    
  /** The proportions of training instances going down each branch. */
  protected double[] m_Prop = null;
    
  /** Class probabilities from the training data. */
  protected double[] m_ClassProbs = null;
    
  /** Minimum number of instances for leaf. */
  protected double m_MinNum = 1.0;
  
  /** The number of attributes considered for a split. */
  protected int m_KValue = 1;

  /** The random seed to use. */
  protected int m_randomSeed = 1;
  
  /** The maximum depth of the tree (0 = unlimited) */
  protected int m_MaxDepth = 0;

  /** a ZeroR model in case no model can be built from the data */
  protected Classifier m_ZeroR;
    
  /**
   * Returns a string describing classifier
   * @return a description suitable for
   * displaying in the explorer/experimenter gui
   */
  public String globalInfo() {

    return  "Class for constructing a tree that considers K randomly " +
      " chosen attributes at each node. Performs no pruning.";
  }
  
  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String minNumTipText() {
    return "The minimum total weight of the instances in a leaf.";
  }

  /**
   * Get the value of MinNum.
   *
   * @return Value of MinNum.
   */
  public double getMinNum() {
    
    return m_MinNum;
  }
  
  /**
   * Set the value of MinNum.
   *
   * @param newMinNum Value to assign to MinNum.
   */
  public void setMinNum(double newMinNum) {
    
    m_MinNum = newMinNum;
  }
  
  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String KValueTipText() {
    return "Sets the number of randomly chosen attributes.";
  }
  
  /**
   * Get the value of K.
   *
   * @return Value of K.
   */
  public int getKValue() {
    
    return m_KValue;
  }
  
  /**
   * Set the value of K.
   *
   * @param k Value to assign to K.
   */
  public void setKValue(int k) {
    
    m_KValue = k;
  }

  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String seedTipText() {
    return "The random number seed used for selecting attributes.";
  }

  /**
   * Set the seed for random number generation.
   *
   * @param seed the seed 
   */
  public void setSeed(int seed) {

    m_randomSeed = seed;
  }
  
  /**
   * Gets the seed for the random number generations
   *
   * @return the seed for the random number generation
   */
  public int getSeed() {

    return m_randomSeed;
  }
  
  /**
   * Returns the tip text for this property
   * 
   * @return 		tip text for this property suitable for
   * 			displaying in the explorer/experimenter gui
   */
  public String maxDepthTipText() {
    return "The maximum depth of the tree, 0 for unlimited.";
  }

  /**
   * Get the maximum depth of trh tree, 0 for unlimited.
   *
   * @return 		the maximum depth.
   */
  public int getMaxDepth() {
    return m_MaxDepth;
  }
  
  /**
   * Set the maximum depth of the tree, 0 for unlimited.
   *
   * @param value 	the maximum depth.
   */
  public void setMaxDepth(int value) {
    m_MaxDepth = value;
  }
  
  /**
   * Lists the command-line options for this classifier.
   * 
   * @return an enumeration over all possible options
   */
  public Enumeration listOptions() {
    
    Vector newVector = new Vector();

    newVector.addElement(new Option(
	"\tNumber of attributes to randomly investigate\n"
	+"\t(<1 = int(log(#attributes)+1)).",
	"K", 1, "-K <number of attributes>"));

    newVector.addElement(new Option(
	"\tSet minimum number of instances per leaf.",
	"M", 1, "-M <minimum number of instances>"));

    newVector.addElement(new Option(
	"\tSeed for random number generator.\n"
	+ "\t(default 1)",
	"S", 1, "-S <num>"));

    newVector.addElement(new Option(
	"\tThe maximum depth of the tree, 0 for unlimited.\n"
	+ "\t(default 0)",
	"depth", 1, "-depth <num>"));

    Enumeration enu = super.listOptions();
    while (enu.hasMoreElements()) {
      newVector.addElement(enu.nextElement());
    }

    return newVector.elements();
  } 

  /**
   * Gets options from this classifier.
   * 
   * @return the options for the current setup
   */
  public String[] getOptions() {
    Vector        result;
    String[]      options;
    int           i;
    
    result = new Vector();
    
    result.add("-K");
    result.add("" + getKValue());
    
    result.add("-M");
    result.add("" + getMinNum());
    
    result.add("-S");
    result.add("" + getSeed());
    
    if (getMaxDepth() > 0) {
      result.add("-depth");
      result.add("" + getMaxDepth());
    }
    
    options = super.getOptions();
    for (i = 0; i < options.length; i++)
      result.add(options[i]);
    
    return (String[]) result.toArray(new String[result.size()]);
  }

  /**
   * Parses a given list of options. <p/>
   * 
   <!-- options-start -->
   * Valid options are: <p/>
   * 
   * <pre> -K &lt;number of attributes&gt;
   *  Number of attributes to randomly investigate
   *  (&lt;1 = int(log(#attributes)+1)).</pre>
   * 
   * <pre> -M &lt;minimum number of instances&gt;
   *  Set minimum number of instances per leaf.</pre>
   * 
   * <pre> -S &lt;num&gt;
   *  Seed for random number generator.
   *  (default 1)</pre>
   * 
   * <pre> -depth &lt;num&gt;
   *  The maximum depth of the tree, 0 for unlimited.
   *  (default 0)</pre>
   * 
   * <pre> -D
   *  If set, classifier is run in debug mode and
   *  may output additional info to the console</pre>
   * 
   <!-- options-end -->
   * 
   * @param options the list of options as an array of strings
   * @throws Exception if an option is not supported
   */
  public void setOptions(String[] options) throws Exception{
    String	tmpStr;
    
    tmpStr = Utils.getOption('K', options);
    if (tmpStr.length() != 0) {
      m_KValue = Integer.parseInt(tmpStr);
    } else {
      m_KValue = 1;
    }
    
    tmpStr = Utils.getOption('M', options);
    if (tmpStr.length() != 0) {
      m_MinNum = Double.parseDouble(tmpStr);
    } else {
      m_MinNum = 1;
    }
    
    tmpStr = Utils.getOption('S', options);
    if (tmpStr.length() != 0) {
      setSeed(Integer.parseInt(tmpStr));