srcomparator.java

来自「用java实现的改进粒子群算法」· Java 代码 · 共 60 行

/**
 * Description: For comparison of goodness in landscape with stoch. ranking.
 *
 * @Applied domain: efficiently for ridge class feasible space (SF), such as
 *  the problem with eqaulity constraints
 *
 * @ Author        Create/Modi     Note
 * Xiaofeng Xie    May 29, 2004
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but 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.
 *
 * Please acknowledge the author(s) if you use this code in any way.
 *
 * @version 1.0
 * @Since MAOS1.2
 *
 * [1] Runarsson T P, Yao X. Stochastic ranking for constrained evolutionary
 * optimization. IEEE Trans. on Evolutionary Computation. 2000, 4 (3): 284-294
 *
 */

package goodness;

import Global.*;

public class SRComparator implements IGoodnessCompareEngine, IUpdateCycleEngine {
  public double Pf = 0.5;

  public SRComparator() {}

  public SRComparator(double pf) {
    this.Pf = pf;
  }

  public void updateCycle(int t) {
    Pf *=0.995;
  }

  /**
   *  check the magnitude of two array, the frontial is more important
   * Stoch ranking: array size = 2
   **/
  public int compare(double[] fit1, double[] fit2) {
    if((fit1[0]==fit2[0])||Pf>Math.random()) {
      return GlobalCompare.compare(fit1[1], fit2[1]);
    } else {
      return GlobalCompare.compare(fit1[0], fit2[0]);
    }
  }

}