equals.java

JGAP（发音"jay-gap"）是一款用Java编写的遗传算法包。提供了基本的遗传算法.你可以使用它来解决一些适用于遗传算法解决的问题.

/*
 * This file is part of JGAP.
 *
 * JGAP offers a dual license model containing the LGPL as well as the MPL.
 *
 * For licencing 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 org.jgap.gp.function;

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

/**
 * The equals operation.
 *
 * @author Klaus Meffert
 * @since 3.0
 */
public class Equals
    extends MathCommand {
  /** String containing the CVS revision. Read out via reflection!*/
  private final static String CVS_REVISION = "$Revision: 1.3 $";

  private Class m_type;

  public Equals(final GPConfiguration a_conf, Class a_type)
      throws InvalidConfigurationException {
    super(a_conf, 2, CommandGene.BooleanClass);
    m_type = a_type;
  }

  protected CommandGene newGeneInternal() {
    try {
      CommandGene gene = new Equals(getGPConfiguration(), m_type);
      return gene;
    } catch (InvalidConfigurationException iex) {
      throw new IllegalStateException(iex.getMessage());
    }
  }

  public String toString() {
    return "Equals(&1, &2)";
  }

  public boolean execute_boolean(ProgramChromosome c, int n, Object[] args) {
    if (m_type == CommandGene.BooleanClass) {
      return c.execute_boolean(n, 0, args) == c.execute_boolean(n, 1, args);
    }
    else if (m_type == CommandGene.IntegerClass) {
      return c.execute_int(n, 0, args) == c.execute_int(n, 1, args);
    }
    else if (m_type == CommandGene.LongClass) {
      return c.execute_long(n, 0, args) == c.execute_long(n, 1, args);
    }
    else if (m_type == CommandGene.DoubleClass) {
      return Math.abs(c.execute_double(n, 0, args) -
                      c.execute_double(n, 1, args)) < DELTA;
    }
    else if (m_type == CommandGene.FloatClass) {
      return Math.abs(c.execute_float(n, 0, args) -
                      c.execute_float(n, 1, args)) < DELTA;
    }
    else if (m_type == CommandGene.VoidClass) {
      return c.execute_object(n, 0, args).equals(c.execute_object(n, 1, args));
    }
    throw new UnsupportedOperationException("Unsupported type " + m_type +
        " for Equals-command!");
  }

  public Class getChildType(IGPProgram a_ind, int a_index) {
    return m_type;
  }
}