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File org.dgpf.search.algorithms.ga.SelectionAlgorithm.java

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/*
 * Copyright (c) 2006 Thomas Weise
 *
 * E-Mail           : tweise@gmx.de
 * Creation Date    : 2006-04-10 06:10:07
 * Original Filename: org.dgpf.search.algorithms.ga.selection.SelectionAlgorithm.java
 * Version          : 2.0.2
 * Last modification: 2006-05-31
 *                by: Thomas Weise
 *
 * License          : GNU LESSER GENERAL PUBLIC LICENSE
 *                    Version 2.1, February 1999
 *                    You should have received a copy of this license along
 *                    with this library; if not, write to the Free Software
 *                    Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *                    MA 02111-1307, USA or download the license under
 *                    http://www.gnu.org/copyleft/lesser.html.
 *
 * Warranty         : This software is provided "as is" without any
 *                    warranty; without even the implied warranty of
 *                    merchantability or fitness for a particular purpose.
 *                    See the Gnu Lesser General Public License for more
 *                    details.
 */


package org.dgpf.search.algorithms.ga;

import java.io.Serializable;

import org.dgpf.search.api.Individual;
import org.dgpf.search.api.SearchAdaptable;
import org.dgpf.search.api.SearchState;
import org.sfc.math.stochastic.Randomizer;

/**
 *
 * This class encapsulates a genetic selection algorithm.
 * Algorithms like tournament selection are provided as default
 * implementations.
 *
 * @author Thomas Weise
 */

public abstract class SelectionAlgorithm  extends SearchAdaptable
  {
/**
 * The sorting algorithm used by the selection algorithm.
 */

  private final SortingAlgorithm  m_sorting ;
  
  
/**
 * Create a selection algorithm using the specified sorting algorithm.
 * @param p_sorting The underlying sorting algorithm.
 */

  protected SelectionAlgorithm(final SortingAlgorithm p_sorting)
    {
    super();
    this.m_sorting = ((p_sorting != null) ? p_sorting :
                       GeneticUtils.DEFAULT_SORTING_ALGORITHM);  
    }
  
/**
 * Select one individual out of the population for reproduction (crossover
 * or mutation). The individuals in the array are ordered by the search's
 * current comparator, with the fittest individual at index <code>0</code>
 * and the worst at index <code>p_count-1</code>.
 * @param p_random        The randomizer to be used for the selection.
 * @param p_individuals   The population of individuals after being
 *                        preprocessed.
 * @param p_count         The count of valid items inside the population
 *                        array.
 * @param <Genotype>      The genotype of the individuals to select.
 * @return  An individual to reproduce.
 */

  public  abstract  <Genotype extends Serializable> Individual<Genotype>
                         select(final Randomizer             p_random,
                                final Individual<Genotype>[] p_individuals,
                                final int                    p_count);

  
/**
 * This method will be called by the search engine whenever it feels like
 * it is time to adapt the current search parameters to the current search
 * state. If you override this method, you must also declare your class
 * as instance of <code>ICloneable</code>.
 * @param p_state The current state of the search.
 * @return  <code>true</code> if and only if the update level should be
 *          resetted, <code>false</code> if everything should continue
 *          normal.
 */

  @Override
  protected boolean  adapt (final SearchState<?> p_state)
    {
    return super.adapt(p_state);
    }

  
/**
 * Obtain a human readable name of the sorting algorithm.
 * @return A human readable name of the sorting algorithm.
 */

  @Override
  public  String  toString()
    {
    return (super.toString() + '[' + this.m_sorting + ']');
    }
  
/**
 * Obtain the sorting algorithm to be applied before selecting.
 * @return The sorting algorithm to be applied before selecting.
 */

  public  SortingAlgorithm  get_sorting_algorithm()
    {
    return this.m_sorting;
    }

/**
 * Check whether this object equals another one. This method is internally
 * invoked by <code>equals()</code>. 
 * @param p_object  The object to compare with.
 * @return <code>true</code> if and only if this object equals to the other
 *         one.
 */

  protected abstract  boolean is_equal  (final Object p_object);
  
/**
 * Check whether this object equals another one.
 * @param p_object  The object to compare with.
 * @return <code>true</code> if and only if this object equals to the other
 *         one.
 */

  @Override
  public  final boolean equals  (final Object p_object)
    {
    if(p_object == thisreturn true;
    
    if(p_object instanceof SelectionAlgorithm)
      {
      return (((SelectionAlgorithm)p_object).m_sorting
                                            .equals(this.m_sorting) &&
                                            this.is_equal(p_object));
      }
    
    return false;
    }
  }

File Information:

file name:SelectionAlgorithm.java
package:org.dgpf.search.algorithms.ga
qualified name:org.dgpf.search.algorithms.ga.SelectionAlgorithm.java
file type:Java Source File
download location:download http://dgpf.sourceforge.net/source/org/dgpf/search/algorithms/ga/SelectionAlgorithm.java
size:5.053 KB (5175 B)
uploaded: 2015-07-22 04:10:59 GMT+0000
last update: 2006-06-01 10:46:54 GMT+0000
last access: 2017-11-18 04:24:40 GMT+0000

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