source: src/main/java/weka/classifiers/rules/PART.java @ 7

/*
 *    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.
 */

/*
 *    PART.java
 *    Copyright (C) 1999 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.classifiers.rules;

import weka.classifiers.Classifier;
import weka.classifiers.AbstractClassifier;
import weka.classifiers.rules.part.MakeDecList;
import weka.classifiers.trees.j48.BinC45ModelSelection;
import weka.classifiers.trees.j48.C45ModelSelection;
import weka.classifiers.trees.j48.ModelSelection;
import weka.core.AdditionalMeasureProducer;
import weka.core.Capabilities;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.RevisionUtils;
import weka.core.Summarizable;
import weka.core.TechnicalInformation;
import weka.core.TechnicalInformationHandler;
import weka.core.Utils;
import weka.core.WeightedInstancesHandler;
import weka.core.TechnicalInformation.Field;
import weka.core.TechnicalInformation.Type;

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

/**
 <!-- globalinfo-start -->
 * Class for generating a PART decision list. Uses separate-and-conquer. Builds a partial C4.5 decision tree in each iteration and makes the "best" leaf into a rule.<br/>
 * <br/>
 * For more information, see:<br/>
 * <br/>
 * Eibe Frank, Ian H. Witten: Generating Accurate Rule Sets Without Global Optimization. In: Fifteenth International Conference on Machine Learning, 144-151, 1998.
 * <p/>
 <!-- globalinfo-end -->
 *
 <!-- technical-bibtex-start -->
 * BibTeX:
 * <pre>
 * &#64;inproceedings{Frank1998,
 *    author = {Eibe Frank and Ian H. Witten},
 *    booktitle = {Fifteenth International Conference on Machine Learning},
 *    editor = {J. Shavlik},
 *    pages = {144-151},
 *    publisher = {Morgan Kaufmann},
 *    title = {Generating Accurate Rule Sets Without Global Optimization},
 *    year = {1998},
 *    PS = {http://www.cs.waikato.ac.nz/\~eibe/pubs/ML98-57.ps.gz}
 * }
 * </pre>
 * <p/>
 <!-- technical-bibtex-end -->
 *
 <!-- options-start -->
 * Valid options are: <p/>
 * 
 * <pre> -C &lt;pruning confidence&gt;
 *  Set confidence threshold for pruning.
 *  (default 0.25)</pre>
 * 
 * <pre> -M &lt;minimum number of objects&gt;
 *  Set minimum number of objects per leaf.
 *  (default 2)</pre>
 * 
 * <pre> -R
 *  Use reduced error pruning.</pre>
 * 
 * <pre> -N &lt;number of folds&gt;
 *  Set number of folds for reduced error
 *  pruning. One fold is used as pruning set.
 *  (default 3)</pre>
 * 
 * <pre> -B
 *  Use binary splits only.</pre>
 * 
 * <pre> -U
 *  Generate unpruned decision list.</pre>
 * 
 * <pre> -J
 *  Do not use MDL correction for info gain on numeric attributes.</pre>
 * 
 * <pre> -Q &lt;seed&gt;
 *  Seed for random data shuffling (default 1).</pre>
 * 
 <!-- options-end -->
 *
 * @author Eibe Frank (eibe@cs.waikato.ac.nz)
 * @version $Revision: 6089 $
 */
public class PART 
  extends AbstractClassifier 
  implements OptionHandler, WeightedInstancesHandler, Summarizable, 
             AdditionalMeasureProducer, TechnicalInformationHandler {

  /** for serialization */
  static final long serialVersionUID = 8121455039782598361L;
  
  /** The decision list */
  private MakeDecList m_root;

  /** Confidence level */
  private float m_CF = 0.25f;

  /** Minimum number of objects */
  private int m_minNumObj = 2;

  /** Use MDL correction? */
  private boolean m_useMDLcorrection = true;         

  /** Use reduced error pruning? */
  private boolean m_reducedErrorPruning = false;

  /** Number of folds for reduced error pruning. */
  private int m_numFolds = 3;

  /** Binary splits on nominal attributes? */
  private boolean m_binarySplits = false;
  
  /** Generate unpruned list? */
  private boolean m_unpruned = false;

  /** The seed for random number generation. */
  private int m_Seed = 1;
    
  /**
   * Returns a string describing classifier
   * @return a description suitable for
   * displaying in the explorer/experimenter gui
   */
  public String globalInfo() {

    return  "Class for generating a PART decision list. Uses "
      + "separate-and-conquer. Builds a partial C4.5 decision tree "
      + "in each iteration and makes the \"best\" leaf into a rule.\n\n"
      + "For more information, see:\n\n"
      + getTechnicalInformation().toString();
  }

  /**
   * Returns an instance of a TechnicalInformation object, containing 
   * detailed information about the technical background of this class,
   * e.g., paper reference or book this class is based on.
   * 
   * @return the technical information about this class
   */
  public TechnicalInformation getTechnicalInformation() {
    TechnicalInformation        result;
    
    result = new TechnicalInformation(Type.INPROCEEDINGS);
    result.setValue(Field.AUTHOR, "Eibe Frank and Ian H. Witten");
    result.setValue(Field.TITLE, "Generating Accurate Rule Sets Without Global Optimization");
    result.setValue(Field.BOOKTITLE, "Fifteenth International Conference on Machine Learning");
    result.setValue(Field.EDITOR, "J. Shavlik");
    result.setValue(Field.YEAR, "1998");
    result.setValue(Field.PAGES, "144-151");
    result.setValue(Field.PUBLISHER, "Morgan Kaufmann");
    result.setValue(Field.PS, "http://www.cs.waikato.ac.nz/~eibe/pubs/ML98-57.ps.gz");
    
    return result;
  }

  /**
   * Returns default capabilities of the classifier.
   *
   * @return      the capabilities of this classifier
   */
  public Capabilities getCapabilities() {
    Capabilities      result;

    if (m_unpruned) 
      result = new MakeDecList(null, m_minNumObj).getCapabilities();
    else if (m_reducedErrorPruning) 
      result = new MakeDecList(null, m_numFolds, m_minNumObj, m_Seed).getCapabilities();
    else
      result = new MakeDecList(null, m_CF, m_minNumObj).getCapabilities();
    
    return result;
  }

  /**
   * Generates the classifier.
   *
   * @param instances the data to train with
   * @throws Exception if classifier can't be built successfully
   */
  public void buildClassifier(Instances instances) 
       throws Exception {

    // can classifier handle the data?
    getCapabilities().testWithFail(instances);

    // remove instances with missing class
    instances = new Instances(instances);
    instances.deleteWithMissingClass();
    
    ModelSelection modSelection;         

    if (m_binarySplits)
      modSelection = new BinC45ModelSelection(m_minNumObj, instances, m_useMDLcorrection);
    else
      modSelection = new C45ModelSelection(m_minNumObj, instances, m_useMDLcorrection);
    if (m_unpruned) 
      m_root = new MakeDecList(modSelection, m_minNumObj);
    else if (m_reducedErrorPruning) 
      m_root = new MakeDecList(modSelection, m_numFolds, m_minNumObj, m_Seed);
    else
      m_root = new MakeDecList(modSelection, m_CF, m_minNumObj);
    m_root.buildClassifier(instances);
    if (m_binarySplits) {
      ((BinC45ModelSelection)modSelection).cleanup();
    } else {
      ((C45ModelSelection)modSelection).cleanup();
    }
  }

  /**
   * Classifies an instance.
   *
   * @param instance the instance to classify
   * @return the classification
   * @throws Exception if instance can't be classified successfully
   */
  public double classifyInstance(Instance instance) 
       throws Exception {

    return m_root.classifyInstance(instance);
  }

  /** 
   * Returns class probabilities for an instance.
   *
   * @param instance the instance to get the distribution for
   * @return the class probabilities
   * @throws Exception if the distribution can't be computed successfully
   */
  public final double [] distributionForInstance(Instance instance) 
       throws Exception {

    return m_root.distributionForInstance(instance);
  }

  /**
   * Returns an enumeration describing the available options.
   *
   * Valid options are: <p>
   *
   * -C confidence <br>
   * Set confidence threshold for pruning. (Default: 0.25) <p>
   *
   * -M number <br>
   * Set minimum number of instances per leaf. (Default: 2) <p>
   *
   * -R <br>
   * Use reduced error pruning. <p>
   *
   * -N number <br>
   * Set number of folds for reduced error pruning. One fold is
   * used as the pruning set. (Default: 3) <p>
   *
   * -B <br>
   * Use binary splits for nominal attributes. <p>
   *
   * -U <br>
   * Generate unpruned decision list. <p>
   *
   * -Q <br>
   * The seed for reduced-error pruning. <p>
   *
   * @return an enumeration of all the available options.
   */
  public Enumeration listOptions() {

    Vector newVector = new Vector(8);

    newVector.
        addElement(new Option("\tSet confidence threshold for pruning.\n" +
                              "\t(default 0.25)",
                              "C", 1, "-C <pruning confidence>"));
    newVector.
        addElement(new Option("\tSet minimum number of objects per leaf.\n" +
                              "\t(default 2)",
                              "M", 1, "-M <minimum number of objects>"));
    newVector.
        addElement(new Option("\tUse reduced error pruning.",
                              "R", 0, "-R"));
    newVector.
        addElement(new Option("\tSet number of folds for reduced error\n" +
                              "\tpruning. One fold is used as pruning set.\n" +
                              "\t(default 3)",
                              "N", 1, "-N <number of folds>"));
    newVector.
        addElement(new Option("\tUse binary splits only.",
                              "B", 0, "-B"));
    newVector.
        addElement(new Option("\tGenerate unpruned decision list.",
                              "U", 0, "-U"));
    newVector.
      addElement(new Option("\tDo not use MDL correction for info gain on numeric attributes.",
                            "J", 0, "-J"));
    newVector.
      addElement(new Option("\tSeed for random data shuffling (default 1).",
                            "Q", 1, "-Q <seed>"));

    return newVector.elements();
  }

  /**
   * Parses a given list of options. <p/>
   * 
   <!-- options-start -->
   * Valid options are: <p/>
   * 
   * <pre> -C &lt;pruning confidence&gt;
   *  Set confidence threshold for pruning.
   *  (default 0.25)</pre>
   * 
   * <pre> -M &lt;minimum number of objects&gt;
   *  Set minimum number of objects per leaf.
   *  (default 2)</pre>
   * 
   * <pre> -R
   *  Use reduced error pruning.</pre>
   * 
   * <pre> -N &lt;number of folds&gt;
   *  Set number of folds for reduced error
   *  pruning. One fold is used as pruning set.
   *  (default 3)</pre>
   * 
   * <pre> -B
   *  Use binary splits only.</pre>
   * 
   * <pre> -U
   *  Generate unpruned decision list.</pre>
   * 
   * <pre> -J
   *  Do not use MDL correction for info gain on numeric attributes.</pre>
   * 
   * <pre> -Q &lt;seed&gt;
   *  Seed for random data shuffling (default 1).</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 {

    // Pruning options
    m_unpruned = Utils.getFlag('U', options);
    m_reducedErrorPruning = Utils.getFlag('R', options);
    m_binarySplits = Utils.getFlag('B', options);
    m_useMDLcorrection = !Utils.getFlag('J', options);
    String confidenceString = Utils.getOption('C', options);
    if (confidenceString.length() != 0) {
      if (m_reducedErrorPruning) {
        throw new Exception("Setting CF doesn't make sense " +
                            "for reduced error pruning.");
      } else {
        m_CF = (new Float(confidenceString)).floatValue();
        if ((m_CF <= 0) || (m_CF >= 1)) {
          throw new Exception("CF has to be greater than zero and smaller than one!");
        } 
      }
    } else {
      m_CF = 0.25f;
    }
    String numFoldsString = Utils.getOption('N', options);
    if (numFoldsString.length() != 0) {
      if (!m_reducedErrorPruning) {
        throw new Exception("Setting the number of folds" +
                            " does only make sense for" +
                            " reduced error pruning.");
      } else {
        m_numFolds = Integer.parseInt(numFoldsString);
      }
    } else {
      m_numFolds = 3;
    }

    // Other options
    String minNumString = Utils.getOption('M', options);
    if (minNumString.length() != 0) {
      m_minNumObj = Integer.parseInt(minNumString);
    } else {
      m_minNumObj = 2;
    }
    String seedString = Utils.getOption('Q', options);
    if (seedString.length() != 0) {
      m_Seed = Integer.parseInt(seedString);
    } else {
      m_Seed = 1;
    }
  }

  /**
   * Gets the current settings of the Classifier.
   *
   * @return an array of strings suitable for passing to setOptions
   */
  public String [] getOptions() {

    String [] options = new String [12];
    int current = 0;

    if (m_unpruned) {
      options[current++] = "-U";
    }
    if (m_reducedErrorPruning) {
      options[current++] = "-R";
    }
    if (m_binarySplits) {
      options[current++] = "-B";
    }
    options[current++] = "-M"; options[current++] = "" + m_minNumObj;
    if (!m_reducedErrorPruning) {
      options[current++] = "-C"; options[current++] = "" + m_CF;
    }
    if (m_reducedErrorPruning) {
      options[current++] = "-N"; options[current++] = "" + m_numFolds;
    }
    options[current++] = "-Q"; options[current++] = "" + m_Seed;
    if (!m_useMDLcorrection) {
      options[current++] = "-J";
    }

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

  /**
   * Returns a description of the classifier
   * 
   * @return a string representation of the classifier
   */
  public String toString() {

    if (m_root == null) {
      return "No classifier built";
    }
    return "PART decision list\n------------------\n\n" + m_root.toString();
  }
  
  /**
   * Returns a superconcise version of the model
   * 
   * @return a concise version of the model
   */
  public String toSummaryString() {

    return "Number of rules: " + m_root.numRules() + "\n";
  }
  
  /**
   * Return the number of rules.
   * @return the number of rules
   */
  public double measureNumRules() {
    return m_root.numRules();
  }
  
  /**
   * Returns an enumeration of the additional measure names
   * @return an enumeration of the measure names
   */
  public Enumeration enumerateMeasures() {
    Vector newVector = new Vector(1);
    newVector.addElement("measureNumRules");
    return newVector.elements();
  }

  /**
   * Returns the value of the named measure
   * @param additionalMeasureName the name of the measure to query for its value
   * @return the value of the named measure
   * @throws IllegalArgumentException if the named measure is not supported
   */
  public double getMeasure(String additionalMeasureName) {
    if (additionalMeasureName.compareToIgnoreCase("measureNumRules") == 0) {
      return measureNumRules();
    } else {
      throw new IllegalArgumentException(additionalMeasureName 
                          + " not supported (PART)");
    }
  }

  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String confidenceFactorTipText() {
    return "The confidence factor used for pruning (smaller values incur "
      + "more pruning).";
  }

  /**
   * Get the value of CF.
   *
   * @return Value of CF.
   */
  public float getConfidenceFactor() {
    
    return m_CF;
  }
  
  /**
   * Set the value of CF.
   *
   * @param v  Value to assign to CF.
   */
  public void setConfidenceFactor(float v) {
    
    m_CF = v;
  }
  
  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String minNumObjTipText() {
    return "The minimum number of instances per rule.";
  }

  /**
   * Get the value of minNumObj.
   *
   * @return Value of minNumObj.
   */
  public int getMinNumObj() {
    
    return m_minNumObj;
  }
  
  /**
   * Set the value of minNumObj.
   *
   * @param v  Value to assign to minNumObj.
   */
  public void setMinNumObj(int v) {
    
    m_minNumObj = v;
  }
  
  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String reducedErrorPruningTipText() {
    return "Whether reduced-error pruning is used instead of C.4.5 pruning.";
  }

  /**
   * Get the value of reducedErrorPruning.
   *
   * @return Value of reducedErrorPruning.
   */
  public boolean getReducedErrorPruning() {
    
    return m_reducedErrorPruning;
  }
  
  /**
   * Set the value of reducedErrorPruning.
   *
   * @param v  Value to assign to reducedErrorPruning.
   */
  public void setReducedErrorPruning(boolean v) {
    
    m_reducedErrorPruning = v;
  }
  
  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String unprunedTipText() {
    return "Whether pruning is performed.";
  }

  /**
   * Get the value of unpruned.
   *
   * @return Value of unpruned.
   */
  public boolean getUnpruned() {
    
    return m_unpruned;
  }
  
  /**
   * Set the value of unpruned.
   *
   * @param newunpruned Value to assign to unpruned.
   */
  public void setUnpruned(boolean newunpruned) {
    
    m_unpruned = newunpruned;
  }

  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String useMDLcorrectionTipText() {
    return "Whether MDL correction is used when finding splits on numeric attributes.";
  }

  /**
   * Get the value of useMDLcorrection.
   *
   * @return Value of useMDLcorrection.
   */
  public boolean getUseMDLcorrection() {
    
    return m_useMDLcorrection;
  }
  
  /**
   * Set the value of useMDLcorrection.
   *
   * @param newuseMDLcorrection Value to assign to useMDLcorrection.
   */
  public void setUseMDLcorrection(boolean newuseMDLcorrection) {
    
    m_useMDLcorrection = newuseMDLcorrection;
  }
  
  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String numFoldsTipText() {
    return "Determines the amount of data used for reduced-error pruning. "
      + " One fold is used for pruning, the rest for growing the rules.";
  }

  /**
   * Get the value of numFolds.
   *
   * @return Value of numFolds.
   */
  public int getNumFolds() {
    
    return m_numFolds;
  }
  
  /**
   * Set the value of numFolds.
   *
   * @param v  Value to assign to numFolds.
   */
  public void setNumFolds(int v) {
    
    m_numFolds = v;
  }
  
  /**
   * 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 seed used for randomizing the data " +
      "when reduced-error pruning is used.";
  }

  /**
   * Get the value of Seed.
   *
   * @return Value of Seed.
   */
  public int getSeed() {
    
    return m_Seed;
  }
  
  /**
   * Set the value of Seed.
   *
   * @param newSeed Value to assign to Seed.
   */
  public void setSeed(int newSeed) {
    
    m_Seed = newSeed;
  }

  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String binarySplitsTipText() {
    return "Whether to use binary splits on nominal attributes when "
      + "building the partial trees.";
  }
  
  /**
   * Get the value of binarySplits.
   *
   * @return Value of binarySplits.
   */
  public boolean getBinarySplits() {
    
    return m_binarySplits;
  }
  
  /**
   * Set the value of binarySplits.
   *
   * @param v  Value to assign to binarySplits.
   */
  public void setBinarySplits(boolean v) {
    
    m_binarySplits = v;
  }
  
  /**
   * Returns the revision string.
   * 
   * @return            the revision
   */
  public String getRevision() {
    return RevisionUtils.extract("$Revision: 6089 $");
  }
  
  /**
   * Main method for testing this class.
   *
   * @param argv command line options 
   */
  public static void main(String [] argv){
    runClassifier(new PART(), argv);
  }
}