lexicographicalcomparator.java

这是多目标进化算法包

/**
 * LexicoGraphicalComparator.java
 *
 * @author Juan J. durillo
 * @version 1.0
 *
*/

package jmetal.qualityIndicator.util;
import java.util.Comparator;


/**
 * This class implements the <code>Comparator</code> interface. It is used
 * to compare points given as <code>double</code>.
 * The order used is the lexicograhphical.
 */
public class LexicoGraphicalComparator implements Comparator{
  
  /** 
   * The compare method compare the objects o1 and o2.
   * @param o1 An object that reference a double[]
   * @param o2 An object that reference a double[]
   * @return -1 if o1 < o1, 1 if o1 > o2 or 0 in other case.
   */
  public int compare(Object o1, Object o2) {
    //Cast to double [] o1 and o2.
    double [] pointOne = (double [])o1;
    double [] pointTwo = (double [])o2;
    
    //To determine the first i, that pointOne[i] != pointTwo[i];
    int index = 0;
    while ((index < pointOne.length) && (index < pointTwo.length) && 
           pointOne[index] == pointTwo[index]) {
      index++;
    }
    if ((index >= pointOne.length) || (index >= pointTwo.length )) {
      return 0;
    } else if (pointOne[index] < pointTwo[index]) {
      return -1;
    } else if (pointOne[index] > pointTwo[index]) {
      return 1;
    }
    return 0;
  } // compare
} // LexicoGraphicalComparator