instance.java

wekaUT是 university texas austin 开发的基于weka的半指导学习(semi supervised learning)的分类器

    }
    return false;
  }

  /**
   * Tests if a specific value is "missing".
   * The given attribute has to belong to a dataset.
   *
   * @param att the attribute
   */
  public boolean isMissing(Attribute att) {

    return isMissing(att.index());
  }

  /**
   * Tests if the given value codes "missing".
   *
   * @param val the value to be tested
   * @return true if val codes "missing"
   */
  public static boolean isMissingValue(double val) {

    return Double.isNaN(val);
  }

  /**
   * Merges this instance with the given instance and returns
   * the result. Dataset is set to null.
   *
   * @param inst the instance to be merged with this one
   * @return the merged instances
   */
  public Instance mergeInstance(Instance inst) {

    int m = 0;
    double [] newVals = new double[numAttributes() + inst.numAttributes()];
    for (int j = 0; j < numAttributes(); j++, m++) {
      newVals[m] = value(j);
    }
    for (int j = 0; j < inst.numAttributes(); j++, m++) {
      newVals[m] = inst.value(j);
    }
    return new Instance(1.0, newVals);
  }

  /**
   * Returns the double that codes "missing".
   *
   * @return the double that codes "missing"
   */
  public static double missingValue() {

    return MISSING_VALUE;
  }

  /**
   * Returns the number of attributes.
   *
   * @return the number of attributes as an integer
   */
  public int numAttributes() {

    return m_AttValues.length;
  }

  /**
   * Returns the number of class labels.
   *
   * @return the number of class labels as an integer if the 
   * class attribute is nominal, 1 otherwise.
   * @exception UnassignedDatasetException if instance doesn't have access to any
   * dataset
   */
  public int numClasses() {
    
    if (m_Dataset == null) {
      throw new UnassignedDatasetException("Instance doesn't have access to a dataset!");
    }
    return m_Dataset.numClasses();
  }

  /**
   * Returns the number of values present. Always the same as numAttributes().
   *
   * @return the number of values
   */
  public int numValues() {

    return m_AttValues.length;
  }

  /** 
   * Replaces all missing values in the instance with the
   * values contained in the given array. A deep copy of
   * the vector of attribute values is performed before the
   * values are replaced.
   *
   * @param array containing the means and modes
   * @exception IllegalArgumentException if numbers of attributes are unequal
   */
  public void replaceMissingValues(double[] array) {
	 
    if ((array == null) || 
	(array.length != m_AttValues.length)) {
      throw new IllegalArgumentException("Unequal number of attributes!");
    }
    freshAttributeVector();
    for (int i = 0; i < m_AttValues.length; i++) {
      if (isMissing(i)) {
	m_AttValues[i] = array[i];
      }
    }
  }

  /**
   * Sets the class value of an instance to be "missing". A deep copy of
   * the vector of attribute values is performed before the
   * value is set to be missing.
   *
   * @exception UnassignedClassException if the class is not set
   * @exception UnassignedDatasetException if the instance doesn't
   * have access to a dataset
   */
  public void setClassMissing() {

    if (classIndex() < 0) {
      throw new UnassignedClassException("Class is not set!");
    }
    setMissing(classIndex());
  }

  /**
   * Sets the class value of an instance to the given value (internal
   * floating-point format).  A deep copy of the vector of attribute
   * values is performed before the value is set.
   *
   * @param value the new attribute value (If the corresponding
   * attribute is nominal (or a string) then this is the new value's
   * index as a double).  
   * @exception UnassignedClassException if the class is not set
   * @exception UnaddignedDatasetException if the instance doesn't
   * have access to a dataset 
   */
  public void setClassValue(double value) {

    if (classIndex() < 0) {
      throw new UnassignedClassException("Class is not set!");
    }
    setValue(classIndex(), value);
  }

  /**
   * Sets the class value of an instance to the given value. A deep
   * copy of the vector of attribute values is performed before the
   * value is set.
   *
   * @param value the new class value (If the class
   * is a string attribute and the value can't be found,
   * the value is added to the attribute).
   * @exception UnassignedClassException if the class is not set
   * @exception UnassignedDatasetException if the dataset is not set
   * @exception IllegalArgumentException if the attribute is not
   * nominal or a string, or the value couldn't be found for a nominal
   * attribute 
   */
  public final void setClassValue(String value) {

    if (classIndex() < 0) {
      throw new UnassignedClassException("Class is not set!");
    }
    setValue(classIndex(), value);
  }

  /**
   * Sets the reference to the dataset. Does not check if the instance
   * is compatible with the dataset. Note: the dataset does not know
   * about this instance. If the structure of the dataset's header
   * gets changed, this instance will not be adjusted automatically.
   *
   * @param instances the reference to the dataset 
   */
  public final void setDataset(Instances instances) {
    
    m_Dataset = instances;
  }

  /**
   * Sets a specific value to be "missing". Performs a deep copy
   * of the vector of attribute values before the value is set to
   * be missing.
   *
   * @param attIndex the attribute's index
   */
  public final void setMissing(int attIndex) {

    setValue(attIndex, MISSING_VALUE);
  }

  /**
   * Sets a specific value to be "missing". Performs a deep copy
   * of the vector of attribute values before the value is set to
   * be missing. The given attribute has to belong to a dataset.
   *
   * @param att the attribute
   */
  public final void setMissing(Attribute att) {

    setMissing(att.index());
  }

  /**
   * Sets a specific value in the instance to the given value 
   * (internal floating-point format). Performs a deep copy
   * of the vector of attribute values before the value is set.
   *
   * @param attIndex the attribute's index 
   * @param value the new attribute value (If the corresponding
   * attribute is nominal (or a string) then this is the new value's
   * index as a double).  
   */
  public void setValue(int attIndex, double value) {
    
    freshAttributeVector();
    m_AttValues[attIndex] = value;
  }

  /**
   * Sets the whole attribute value array
   *
   * @author Sugato Basu
   * @param attIndex the attribute's index 
   * @param array the attribute value array  
   */
  public void setValueArray(double [] array) {
    
    freshAttributeVector();
    m_AttValues = array;
  }
  
  /**
   * Sets a specific value in the instance to the given value 
   * (internal floating-point format). Performs a deep copy
   * of the vector of attribute values before the value is set.
   * Does exactly the same thing as setValue().
   *
   * @param indexOfIndex the index of the attribute's index 
   * @param value the new attribute value (If the corresponding
   * attribute is nominal (or a string) then this is the new value's
   * index as a double).  
   */
  public void setValueSparse(int indexOfIndex, double value) {
    
    freshAttributeVector();
    m_AttValues[indexOfIndex] = value;
  }

  /**
   * Sets a value of a nominal or string attribute to the given
   * value. Performs a deep copy of the vector of attribute values
   * before the value is set.
   *
   * @param attIndex the attribute's index
   * @param value the new attribute value (If the attribute
   * is a string attribute and the value can't be found,
   * the value is added to the attribute).
   * @exception UnassignedDatasetException if the dataset is not set
   * @exception IllegalArgumentException if the selected
   * attribute is not nominal or a string, or the supplied value couldn't 
   * be found for a nominal attribute 
   */
  public final void setValue(int attIndex, String value) {
    
    int valIndex;

    if (m_Dataset == null) {
      throw new UnassignedDatasetException("Instance doesn't have access to a dataset!");
    }
    if (!attribute(attIndex).isNominal() &&
	!attribute(attIndex).isString()) {
      throw new IllegalArgumentException("Attribute neither nominal nor string!");
    }
    valIndex = attribute(attIndex).indexOfValue(value);
    if (valIndex == -1) {
      if (attribute(attIndex).isNominal()) {
	throw new IllegalArgumentException("Value not defined for given nominal attribute!");
      } else {
	attribute(attIndex).forceAddValue(value);
	valIndex = attribute(attIndex).indexOfValue(value);
      }
    }
    setValue(attIndex, (double)valIndex); 
  }

  /**
   * Sets a specific value in the instance to the given value
   * (internal floating-point format). Performs a deep copy of the
   * vector of attribute values before the value is set, so if you are
   * planning on calling setValue many times it may be faster to
   * create a new instance using toDoubleArray.  The given attribute
   * has to belong to a dataset.
   *
   * @param att the attribute 
   * @param value the new attribute value (If the corresponding
   * attribute is nominal (or a string) then this is the new value's
   * index as a double).  
   */
  public final void setValue(Attribute att, double value) {

    setValue(att.index(), value);
  }

  /**
   * Sets a value of an nominal or string attribute to the given
   * value. Performs a deep copy of the vector of attribute values
   * before the value is set, so if you are planning on calling setValue many
   * times it may be faster to create a new instance using toDoubleArray.
   * The given attribute has to belong to a dataset.
   *
   * @param att the attribute
   * @param value the new attribute value (If the attribute
   * is a string attribute and the value can't be found,
   * the value is added to the attribute).
   * @exception IllegalArgumentException if the the attribute is not
   * nominal or a string, or the value couldn't be found for a nominal
   * attribute 
   */
  public final void setValue(Attribute att, String value) {

    if (!att.isNominal() &&
	!att.isString()) {
      throw new IllegalArgumentException("Attribute neither nominal nor string!");
    }
    int valIndex = att.indexOfValue(value);
    if (valIndex == -1) {
      if (att.isNominal()) {
	throw new IllegalArgumentException("Value not defined for given nominal attribute!");
      } else {
	att.forceAddValue(value);
	valIndex = att.indexOfValue(value);
      }
    }
    setValue(att.index(), (double)valIndex);
  }

  /**
   * Sets the weight of an instance.
   *
   * @param weight the weight
   */
  public final void setWeight(double weight) {

    m_Weight = weight;
  }

  /** 
   * Returns the string value of a nominal, string, or date attribute
   * for the instance.
   *
   * @param attIndex the attribute's index
   * @return the value as a string
   * @exception IllegalArgumentException if the attribute is not a nominal,
   * string, or date attribute.