//      e04gy Example Program Text
//      C# version, NAG Copyright 2008
using System;
using NagLibrary;
using System.Globalization;
using System.IO;
namespace NagDotNetExamples
{
  public class E04GYE
  {
    static int m = 15;
    static int nt = 3;
    static double[] ruser = new double[m + m * nt];
    static int[] iuser = new int[1];
    static string datafile = "ExampleData/e04gye.d";
    // as a command line argument. It defaults to the named file specified below otherwise.
    //
    static void Main(String[] args)
    {
      if (args.Length == 1)
      {
        datafile = args[0];
      }
      StartExample();
    }
    public static void StartExample()
    {
      E04.E04GY_LSFUN2 lsfun2E04GY = new E04.E04GY_LSFUN2(lsfun2);
      try
      {
        DataReader sr = new DataReader(datafile);
      double fsumsq = 0.0;
      int i,  ifail,  j,  k;
      int n = 3;
      double[,] t = new double[m, nt];
      double[] x = new double[n];
      double[] y = new double[m];
      Console.WriteLine("e04gy Example Program Results");
      //      Skip heading in data file
      sr.Reset();
      //
      //      Observations of tj (j = 1, 2, 3) are held in t[i-1, j-1]
      //      (i = 1, 2, . . . , 15)
      //
      iuser[0] = nt;
      k = m;
      for (i = 1; i <= m; i++)
      {
        sr.Reset();
        y[i - 1] = double.Parse(sr.Next(), CultureInfo.InvariantCulture);
        for (j = 1; j <= nt; j++)
        {
          t[i - 1, j - 1] = double.Parse(sr.Next(), CultureInfo.InvariantCulture);
        }
        ruser[i - 1] = y[i - 1];
        for (j = 1; j <= nt; j++)
        {
          ruser[k + j - 1] = t[i - 1, j - 1];
        }
        k = k + nt;
      }
      //
      x[0] = 0.50e0;
      x[1] = 1.00e0;
      x[2] = 1.50e0;
      //
      //
      E04.e04gy(m, n, lsfun2E04GY, x, out fsumsq, out ifail);
      //
      if (ifail < 0)
      {
        Console.WriteLine("");
        Console.WriteLine(" ** e04gy 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) && (ifail != 9))
        {
          Console.WriteLine("");
          Console.WriteLine("  {0}{1,12:f4}", "On exit, the sum of squares is", fsumsq);
          Console.Write(" " + " {0}", "at the point");
          for (j = 1; j <= n; j++)
          {
            Console.Write(" " + " {0, 12:f4}", x[j - 1]);
          }
          Console.WriteLine(" ");
        }
      }
      //
    }
    catch (Exception e)
    {
      Console.WriteLine(e.Message);
      Console.WriteLine( "Exception Raised");
    }
  }
  //
  public static void lsfun2(int m, int n, double[] xc, double[] fvec, double[,
  ] fjac)
  {
    //      Routine to evaluate the residuals and their 1st derivatives.
    double denom,  dummy;
    int i,  k;
    k = m;
    for (i = 1; i <= m; i++)
    {
      denom = xc[1] * ruser[k + 2 - 1] + xc[2] * ruser[k + 3 - 1];
      fvec[i - 1] = xc[0] + ruser[k + 1 - 1] / denom - ruser[i - 1];
      fjac[i - 1, 0] = 1.00e0;
      dummy = -1.00e0 / (denom * denom);
      fjac[i - 1, 1] = ruser[k + 1 - 1] * ruser[k + 2 - 1] * dummy;
      fjac[i - 1, 2] = ruser[k + 1 - 1] * ruser[k + 3 - 1] * dummy;
      k = k + iuser[0];
    }
  }
}
}