weka 之 聚类

package weka.clusterers;

import weka.core.Capabilities;
import weka.core.Instance;
import weka.core.Instances;

/**
 * Interface for clusterers. Clients will typically extend either
 * AbstractClusterer or AbstractDensityBasedClusterer.
 *
 * @author Mark Hall ([e-mail])
 * @revision $Revision: 1.18 $
 */
public interface Clusterer {

  /**
   * Generates a clusterer. Has to initialize all fields of the clusterer
   * that are not being set via options.
   *
   * @param data set of instances serving as training data 
   * @exception Exception if the clusterer has not been 
   * generated successfully
   */
  void buildClusterer(Instances data) throws Exception;

  /**
   * Classifies a given instance. Either this or distributionForInstance()
   * needs to be implemented by subclasses.
   *
   * @param instance the instance to be assigned to a cluster
   * @return the number of the assigned cluster as an integer
   * @exception Exception if instance could not be clustered
   * successfully
   */
  int clusterInstance(Instance instance) throws Exception;

  /**
   * Predicts the cluster memberships for a given instance.  Either
   * this or clusterInstance() needs to be implemented by subclasses.
   *
   * @param instance the instance to be assigned a cluster.
   * @return an array containing the estimated membership 
   * probabilities of the test instance in each cluster (this 
   * should sum to at most 1)
   * @exception Exception if distribution could not be 
   * computed successfully 
   */
  public double[] distributionForInstance(Instance instance) throws Exception;

  /**
   * Returns the number of clusters.
   *
   * @return the number of clusters generated for a training dataset.
   * @exception Exception if number of clusters could not be returned
   * successfully
   */
  int numberOfClusters() throws Exception;

  /** 
   * Returns the Capabilities of this clusterer. Derived classifiers have to
   * override this method to enable capabilities.
   *
   * @return            the capabilities of this object
   * @see               Capabilities
   */
  public Capabilities getCapabilities();
  
}