/**
 * Description: Benchmark function (Michalewicz's G3).
 * X*(Optimal point):
 * X1~X10: 1/sqrt(n)=0.31622776601683794 (as n=10)
 * Y*(Optimal value)
 * Y1=1
 *
 * @ Author        Create/Modi     Note
 * Xiaofeng Xie    Dec 28, 2001
 * Xiaofeng Xie    Mar 02, 2003
 * Xiaofeng Xie    May 11, 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 MAOS1.0
 *
 * @References:
 * [1] Koziel S, Michalewicz Z. Evolutionary algorithms, homomorphous
 * mappings, and constrained parameter optimization. Evolutionary
 * Computation, 1999, 7: 19-44
 */

package problem.constrained;

import problem.*;
import Global.*;

public class Michalewicz_G3 extends ProblemEncoder {
  static final int NX = 10;
  static final int NY = 2;
  public Michalewicz_G3() throws Exception {
    super(NX, NY);
    for(int i=0; i<NX; i++) {
      setDefaultXAt(i, 0, 1);
    }

    setDefaultYAt(0, BasicBound.MAXDOUBLE, BasicBound.MAXDOUBLE);
    setDefaultYAt(1, 0, 1E-4);
  }

  protected double calcTargetAt(int index, double[] VX) {
    double value = 0;
    switch(index) {
      case 0:
        value = Math.pow(Math.sqrt(NX),NX);
        for (int j=0; j<NX; j++) {
          value *= VX[j];
        }
        break;
      case 1:
        value = -1;
        for (int j=0; j<NX; j++) {
          value += Math.pow(VX[j],2);
        }
        value = Math.abs(value);
        break;
    default:
      return Double.NaN;
    }
    return value;
  }
}