attributeselectedclassifier.java

分类的属性选择算法

      +"during the attribute selection phase before the classifier is "
      +"invoked.";
  }

  /**
   * Sets the attribute evaluator
   *
   * @param evaluator the evaluator with all options set.
   */
  public void setEvaluator(ASEvaluation evaluator) {
    m_Evaluator = evaluator;
  }

  /**
   * Gets the attribute evaluator used
   *
   * @return the attribute evaluator
   */
  public ASEvaluation getEvaluator() {
    return m_Evaluator;
  }

  /**
   * Gets the evaluator specification string, which contains the class name of
   * the attribute evaluator and any options to it
   *
   * @return the evaluator string.
   */
  protected String getEvaluatorSpec() {
    
    ASEvaluation e = getEvaluator();
    if (e instanceof OptionHandler) {
      return e.getClass().getName() + " "
	+ Utils.joinOptions(((OptionHandler)e).getOptions());
    }
    return e.getClass().getName();
  }

  /**
   * Returns the tip text for this property
   * @return tip text for this property suitable for
   * displaying in the explorer/experimenter gui
   */
  public String searchTipText() {
    return "Set the search method. This search method is used "
      +"during the attribute selection phase before the classifier is "
      +"invoked.";
  }
  
  /**
   * Sets the search method
   *
   * @param search the search method with all options set.
   */
  public void setSearch(ASSearch search) {
    m_Search = search;
  }

  /**
   * Gets the search method used
   *
   * @return the search method
   */
  public ASSearch getSearch() {
    return m_Search;
  }

  /**
   * Gets the search specification string, which contains the class name of
   * the search method and any options to it
   *
   * @return the search string.
   */
  protected String getSearchSpec() {
    
    ASSearch s = getSearch();
    if (s instanceof OptionHandler) {
      return s.getClass().getName() + " "
	+ Utils.joinOptions(((OptionHandler)s).getOptions());
    }
    return s.getClass().getName();
  }

  /**
   * Build the classifier on the dimensionally reduced data.
   *
   * @param data the training data
   * @exception Exception if the classifier could not be built successfully
   */
  public void buildClassifier(Instances data) throws Exception {
    if (m_Classifier == null) {
      throw new Exception("No base classifier has been set!");
    }

    if (m_Evaluator == null) {
      throw new Exception("No attribute evaluator has been set!");
    }

    if (m_Search == null) {
      throw new Exception("No search method has been set!");
    }
   
    Instances newData = new Instances(data);
    newData.deleteWithMissingClass();
    if (newData.classAttribute().isNominal()) {
      m_numClasses = newData.classAttribute().numValues();
    } else {
      m_numClasses = 1;
    }

    m_AttributeSelection = new AttributeSelection();
    m_AttributeSelection.setEvaluator(m_Evaluator);
    m_AttributeSelection.setSearch(m_Search);
    long start = System.currentTimeMillis();
    m_AttributeSelection.SelectAttributes(newData);
    long end = System.currentTimeMillis();
    newData = m_AttributeSelection.reduceDimensionality(newData);
    m_Classifier.buildClassifier(newData);
    long end2 = System.currentTimeMillis();
    m_numAttributesSelected = m_AttributeSelection.numberAttributesSelected();
    m_ReducedHeader = new Instances(newData, 0);
    m_selectionTime = (double)(end - start);
    m_totalTime = (double)(end2 - start);
  }

  /**
   * Classifies a given instance after attribute selection
   *
   * @param instance the instance to be classified
   * @exception Exception if instance could not be classified
   * successfully
   */
  public double [] distributionForInstance(Instance instance)
    throws Exception {

    if (m_AttributeSelection == null) {
      throw new Exception("AttributeSelectedClassifier: No model built yet!");
    }
    Instance newInstance = m_AttributeSelection.reduceDimensionality(instance);

    if (m_Classifier instanceof DistributionClassifier) {
      return ((DistributionClassifier)m_Classifier)
	.distributionForInstance(newInstance);
    }

    double pred = m_Classifier.classifyInstance(newInstance);
    double [] result = new double[m_numClasses];
    if (Instance.isMissingValue(pred)) {
      return result;
    }
    switch (instance.classAttribute().type()) {
    case Attribute.NOMINAL:
      result[(int) pred] = 1.0;
      break;
    case Attribute.NUMERIC:
      result[0] = pred;
      break;
    default:
      throw new Exception("Unknown class type");
    }
    return result;
  }

  /**
   * Output a representation of this classifier
   */
  public String toString() {
    if (m_AttributeSelection == null) {
      return "AttributeSelectedClassifier: No model built yet.";
    }

    StringBuffer result = new StringBuffer();
    result.append("AttributeSelectedClassifier:\n\n");
    result.append(m_AttributeSelection.toResultsString());
    result.append("\n\nHeader of reduced data:\n"+m_ReducedHeader.toString());
    result.append("\n\nClassifier Model\n"+m_Classifier.toString());

    return result.toString();
  }

  /**
   * Additional measure --- number of attributes selected
   * @return the number of attributes selected
   */
  public double measureNumAttributesSelected() {
    return m_numAttributesSelected;
  }

  /**
   * Additional measure --- time taken (milliseconds) to select the attributes
   * @return the time taken to select attributes
   */
  public double measureSelectionTime() {
    return m_selectionTime;
  }

  /**
   * Additional measure --- time taken (milliseconds) to select attributes
   * and build the classifier
   * @return the total time (select attributes + build classifier)
   */
  public double measureTime() {
    return m_totalTime;
  }

  /**
   * Returns an enumeration of the additional measure names
   * @return an enumeration of the measure names
   */
  public Enumeration enumerateMeasures() {
    Vector newVector = new Vector(3);
    newVector.addElement("measureNumAttributesSelected");
    newVector.addElement("measureSelectionTime");
    newVector.addElement("measureTime");
    if (m_Classifier instanceof AdditionalMeasureProducer) {
      Enumeration en = ((AdditionalMeasureProducer)m_Classifier).
	enumerateMeasures();
      while (en.hasMoreElements()) {
	String mname = (String)en.nextElement();
	newVector.addElement(mname);
      }
    }
    return newVector.elements();
  }
  
  /**
   * Returns the value of the named measure
   * @param measureName the name of the measure to query for its value
   * @return the value of the named measure
   * @exception IllegalArgumentException if the named measure is not supported
   */
  public double getMeasure(String additionalMeasureName) {
    if (additionalMeasureName.compareTo("measureNumAttributesSelected") == 0) {
      return measureNumAttributesSelected();
    } else if (additionalMeasureName.compareTo("measureSelectionTime") == 0) {
      return measureSelectionTime();
    } else if (additionalMeasureName.compareTo("measureTime") == 0) {
      return measureTime();
    } else if (m_Classifier instanceof AdditionalMeasureProducer) {
      return ((AdditionalMeasureProducer)m_Classifier).
	getMeasure(additionalMeasureName);
    } else {
      throw new IllegalArgumentException(additionalMeasureName 
			  + " not supported (AttributeSelectedClassifier)");
    }
  }

  /**
   * Main method for testing this class.
   *
   * @param argv should contain the following arguments:
   * -t training file [-T test file] [-c class index]
   */
  public static void main(String [] argv) {

    try {
      System.out.println(Evaluation
			 .evaluateModel(new AttributeSelectedClassifier(),
					argv));
    } catch (Exception e) {
      System.err.println(e.getMessage());
      e.printStackTrace();
    }
  }
}