/********************************************************
 * BCL Example Problems
 * ====================
 *
 * file xbairport.java
 * ```````````````````
 * QCQP problem by
 * Rodrigo de Barros Nabholz & Maria Aparecida Diniz Ehrhardt
 * November 1994, DMA - IMECC- UNICAMP.
 * Based on AMPL model airport.mod by Hande Y. Benson
 * (Source: http://www.orfe.princeton.edu/~rvdb/ampl/nlmodels/ )
 *
 * (c) 2008-2024 Fair Isaac Corporation
 * author: S.Heipcke, June 2008, rev. Dec. 2011
 ********************************************************/

import com.dashoptimization.*;
import java.io.*;

public class xbairport {
  static final int N = 42;

  static final double CX[] = {
    -6.3, -7.8, -9, -7.2, -5.7, -1.9, -3.5, -0.5, 1.4, 4, 2.1, 5.5, 5.7, 5.7, 3.8, 5.3, 4.7, 3.3, 0,
    -1, -0.4, 4.2, 3.2, 1.7, 3.3, 2, 0.7, 0.1, -0.1, -3.5, -4, -2.7, -0.5, -2.9, -1.2, -0.4, -0.1,
    -1, -1.7, -2.1, -1.8, 0
  };
  static final double CY[] = {
    8, 5.1, 2, 2.6, 5.5, 7.1, 5.9, 6.6, 6.1, 5.6, 4.9, 4.7, 4.3, 3.6, 4.1, 3, 2.4, 3, 4.7, 3.4, 2.3,
    1.5, 0.5, -1.7, -2, -3.1, -3.5, -2.4, -1.3, 0, -1.7, -2.1, -0.4, -2.9, -3.4, -4.3, -5.2, -6.5,
    -7.5, -6.4, -5.1, 0
  };
  static final double R[] = {
    0.09, 0.3, 0.09, 0.45, 0.5, 0.04, 0.1, 0.02, 0.02, 0.07, 0.4, 0.045, 0.05, 0.056, 0.36, 0.08,
    0.07, 0.36, 0.67, 0.38, 0.37, 0.05, 0.4, 0.66, 0.05, 0.07, 0.08, 0.3, 0.31, 0.49, 0.09, 0.46,
    0.12, 0.07, 0.07, 0.09, 0.05, 0.13, 0.16, 0.46, 0.25, 0.1
  };

  public static void main(String[] args) throws IOException {
    try (XPRBprob prob = new XPRBprob("airport"); /* Initialize BCL and create a new problem */
        XPRBexprContext context =
            new XPRBexprContext() /* Release XPRBexpr instances at end of block. */) {
      int i, j;
      XPRBvar[] x, y; /* x-/y-coordinates to determine */
      XPRBexpr qe;
      XPRBctr cobj, c;

      /**** VARIABLES ****/
      x = new XPRBvar[N];
      for (i = 0; i < N; i++) x[i] = prob.newVar("x(" + (i + 1) + ")", XPRB.PL, -10, 10);
      y = new XPRBvar[N];
      for (i = 0; i < N; i++) y[i] = prob.newVar("y(" + (i + 1) + ")", XPRB.PL, -10, 10);

      /****OBJECTIVE****/
      /* Minimize the total distance between all points */
      /*  sum(i in 1..N-1,j in i+1..N) ((x(i)-x(j))^2+(y(i)-y(j))^2)  */
      qe = new XPRBexpr();
      for (i = 0; i < N - 1; i++)
        for (j = i + 1; j < N; j++)
          qe.add((x[i].add(x[j].mul(-1))).sqr()).add((y[i].add(y[j].mul(-1))).sqr());
      cobj = prob.newCtr("TotDist", qe);
      prob.setObj(cobj); /* Set objective function */

      /**** CONSTRAINTS ****/
      /* All points within given distance of their target location */
      /*  (x(i)-CX(i))^2+(y(i)-CY(i))^2 <= R(i)  */
      for (i = 0; i < N; i++)
        c =
            prob.newCtr(
                "LimDist", (x[i].add(-CX[i])).sqr().add((y[i].add(-CY[i])).sqr()).lEql(R[i]));

      /****SOLVING + OUTPUT****/
      prob.setSense(XPRB.MINIM); /* Choose the sense of optimization */

      /* Problem printing and matrix output: */
      /*
        prob.print();
        prob.exportProb(XPRB.MPS, "airport");
        prob.exportProb(XPRB.LP, "airport");
      */

      prob.lpOptimize(""); /* Solve the problem */

      System.out.println("Solution: " + prob.getObjVal());
      for (i = 0; i < N; i++)
        System.out.println(
            x[i].getName() + ": " + x[i].getSol() + ", " + y[i].getName() + ": " + y[i].getSol());
    }
  }
}