//      e04ly Example Program Text
//      C# version, NAG Copyright 2008
using System;
using NagLibrary;
using System.Globalization;
using System.IO;
namespace NagDotNetExamples
{
  public class E04LYE
  {
    static void Main(String[] args)
    {
      StartExample();
    }
    public static void StartExample()
    {
      E04.E04LY_FUNCT2 funct2E04LY = new E04.E04LY_FUNCT2(funct2);
      E04.E04LY_HESS2 hess2E04LY = new E04.E04LY_HESS2(hess2);
      try
      {
        double f = 0.0;
        int ibound,  ifail,  j;
        int n = 4;
        int liw = n + 2;
        int lw = n * (n + 7);
        double[] bl = new double[n];
        double[] bu = new double[n];
        double[] g = new double[n];
        double[] ruser = new double[1];
        double[] w = new double[lw];
        double[] x = new double[n];
        int[] iuser = new int[1];
        int[] iw = new int[liw];
        Console.WriteLine("e04ly Example Program Results");
        x[0] = 3.00e0;
        x[1] = -1.00e0;
        x[2] = 0.00e0;
        x[3] = 1.00e0;
        ibound = 0;
        bl[0] = 1.00e0;
        bu[0] = 3.00e0;
        bl[1] = -2.00e0;
        bu[1] = 0.00e0;
        //
        //      x[2] is unconstrained, so we set bl[2] to a large negative
        //      number and bu[2] to a large positive number.
        //
        bl[2] = -1.00e6;
        bu[2] = 1.00e6;
        bl[3] = 1.00e0;
        bu[3] = 3.00e0;
        //
        E04.e04ly(n, ibound, funct2E04LY, hess2E04LY, bl, bu, x, out f, g, out ifail);
        //
        if (ifail < 0)
        {
          Console.WriteLine("");
          Console.WriteLine(" ** e04ly returned with ifail = {0, 3}", ifail);
        }
        else
        {
          if (ifail != 0)
          {
            Console.WriteLine("");
            Console.WriteLine("  {0}{1,3}{2}", "Error exit type", ifail, " - see method document");
          }
          if (ifail != 1)
          {
            Console.WriteLine("");
            Console.WriteLine("  {0}{1,9:f4}", "Function value on exit is ", f);
            Console.Write(" " + " {0}", "at the point");
            for (j = 1; j <= n; j++)
            {
              Console.Write(" " + " {0, 8:f4}", x[j - 1]);
            }
            Console.WriteLine(" ");
            Console.WriteLine(" {0}", "The corresponding (machine dependent) gradient is");
            for (j = 1; j <= n; j++)
            {
              Console.Write(" " + " {0, 12:e4}", g[j - 1]);
            }
            Console.WriteLine(" ");
          }
        }
        //
      }
      catch (Exception e)
      {
        Console.WriteLine(e.Message);
        Console.WriteLine( "Exception Raised");
      }
    }
    //
    public static void funct2(int n, double[] xc, ref double fc, double[] gc)
    {
      //      Routine to evaluate objective function and its 1st derivatives.
      double x1,  x2,  x3,  x4;
      x1 = xc[0];
      x2 = xc[1];
      x3 = xc[2];
      x4 = xc[3];
      fc = ((x1 + 10.00e0 * x2)) * ((x1 + 10.00e0 * x2)) + 5.00e0 * ((x3 - x4)) * ((x3 - x4)) + Math.Pow((x2 - 2.00e0 * x3), 4) + 10.00e0 * Math.Pow((x1 - x4), 4);
      gc[0] = 2.00e0 * (x1 + 10.00e0 * x2) + 40.00e0 * Math.Pow((x1 - x4), 3);
      gc[1] = 20.00e0 * (x1 + 10.00e0 * x2) + 4.00e0 * Math.Pow((x2 - 2.00e0 * x3), 3);
      gc[2] = 10.00e0 * (x3 - x4) - 8.00e0 * Math.Pow((x2 - 2.00e0 * x3), 3);
      gc[3] = -10.00e0 * (x3 - x4) - 40.00e0 * Math.Pow((x1 - x4), 3);
    }
    //
    public static void hess2(int n, double[] xc, double[] heslc, double[] hesdc)
    {
      //      Routine to evaluate 2nd derivatives.
      double x1,  x2,  x3,  x4;
      x1 = xc[0];
      x2 = xc[1];
      x3 = xc[2];
      x4 = xc[3];
      hesdc[0] = 2.00e0 + 120.00e0 * ((x1 - x4)) * ((x1 - x4));
      hesdc[1] = 200.00e0 + 12.00e0 * ((x2 - 2.00e0 * x3)) * ((x2 - 2.00e0 * x3));
      hesdc[2] = 10.00e0 + 48.00e0 * ((x2 - 2.00e0 * x3)) * ((x2 - 2.00e0 * x3));
      hesdc[3] = 10.00e0 + 120.00e0 * ((x1 - x4)) * ((x1 - x4));
      heslc[0] = 20.00e0;
      heslc[1] = 0.00e0;
      heslc[2] = -24.00e0 * ((x2 - 2.00e0 * x3)) * ((x2 - 2.00e0 * x3));
      heslc[3] = -120.00e0 * ((x1 - x4)) * ((x1 - x4));
      heslc[4] = 0.00e0;
      heslc[5] = -10.00e0;
    }
  }
}