nodevalidator.java

JGAP是一种遗传算法和遗传规划的组成部分提供了一个Java框架。它提供了基本的遗传机制

/*
 * This file is part of JGAP.
 *
 * JGAP offers a dual license model containing the LGPL as well as the MPL.
 *
 * For licensing information please see the file license.txt included with JGAP
 * or have a look at the top of class org.jgap.Chromosome which representatively
 * includes the JGAP license policy applicable for any file delivered with JGAP.
 */
package examples.gp.monalisa.core;

import org.jgap.gp.*;
import org.jgap.gp.function.*;
import org.jgap.gp.impl.*;

/**
 * Validates evolved nodes for the Mona Lisa painting problem.
 *
 * @author Klaus Meffert
 * @since 3.4
 */
public class NodeValidator
    implements INodeValidator {

  /** String containing the CVS revision. Read out via reflection!*/
  private final static String CVS_REVISION = "$Revision: 1.1 $";

  /**
   * Validates a_node in the context of a_chrom during evolution. Considers the
   * recursion level (a_recursLevel), the type needed (a_type) for the node, the
   * functions available (a_functionSet) and the depth of the whole chromosome
   * needed (a_depth), and whether grow mode is used (a_grow is true) or not.
   *
   * @param a_chrom the chromosome that will contain the node, if valid (ignored
   * in this implementation)
   * @param a_node the node selected and to be validated
   * @param a_rootNode the root node of a_node, may be null for top nodes
   * @param a_tries number of times the validator has been called, useful for
   * stopping by returning true if the number exceeds a limit
   * @param a_num the chromosome's index in the individual of this chromosome
   * @param a_recurseLevel level of recursion
   * @param a_type the return type of the node needed
   * @param a_functionSet the array of available functions (ignored in this
   * implementation)
   * @param a_depth the needed depth of the program chromosome
   * @param a_grow true: use grow mode, false: use full mode (ignored in this
   * implementation)
   * @param a_childIndex index of the child in the parent node to which it
   * belongs (-1 if node is root node)
   * @param a_fullProgram true: whole program is available in a_chrom
   * @return true: node is valid; false: node is invalid
   *
   * @author Klaus Meffert
   * @since 3.0
   */
  public boolean validate(ProgramChromosome a_chrom, CommandGene a_node,
                          CommandGene a_rootNode,
                          int a_tries, int a_num, int a_recurseLevel,
                          Class a_type, CommandGene[] a_functionSet,
                          int a_depth, boolean a_grow, int a_childIndex,
                          boolean a_fullProgram) {
    if (a_fullProgram) {
      return true;
    }
    // Guard to avoid endless validation.
    // ----------------------------------
    if (a_tries > 10) {
      return true;
    }
//    // SubProgram forbidden other than as root.
//    // ----------------------------------------
//    if (a_recurseLevel > 0 && a_node.getClass() == SubProgram.class) {
//      return false;
//    }
    // SubProgram wanted as root.
    // --------------------------
    if (a_recurseLevel == 0 && a_node.getClass() != SubProgram.class) {
      return false;
    }
//    // SubProgramm needed directly under root
//    if (a_recurseLevel == 1 && a_depth == 1
//        && a_node.getClass() != SubProgram.class) {
//      return false;
//    }
    return true;
  }
}