//      f08fb Example Program Text
//      C# version, NAG Copyright 2008
using System;
using NagLibrary;
using System.Globalization;
using System.Threading;
namespace NagDotNetExamples
{
  public class F08FBE
  {
    const double zero=0.00e+0;
    static string datafile = "ExampleData/f08fbe.d";
    static void Main(String[] args)
    {
      if (args.Length == 1)
      {
        datafile = args[0];
      }
  StartExample();

    }
    public static void StartExample()
    {
      try
      {
        DataReader sr = new DataReader(datafile);
        double abstol,   vl,   vu; int i,  il,  info,  iu,  j,  m,  n;
        //      Skip heading in data file
        sr.Reset();
        sr.Reset();
        n = int.Parse(sr.Next());
        double[,] a = new double[n, n];
        double[] w = new double[n];
        double[,] z = new double[n, n];
        int[] jfail = new int[n];
        int ifail;
        il = 0;
        iu = 0;
        Console.WriteLine("f08fb Example Program Results");
        Console.WriteLine("");
        if (n > 0)
        {
          // 
          //         Read the lower and upper bounds of the interval to be searched,
          //         and read the upper triangular part of the matrix A from data
          //         file
          // 
          sr.Reset();
          vl = double.Parse(sr.Next(), CultureInfo.InvariantCulture);
          vu = double.Parse(sr.Next(), CultureInfo.InvariantCulture);
          sr.Reset();
          for (i = 1 ; i <= n ; i++)
          {
            for (j = i ; j <= n ; j++)
            {
              a[i - 1 , j - 1] = double.Parse(sr.Next(), CultureInfo.InvariantCulture);
            }
          }
          // 
          //         Set the absolute error tolerance for eigenvalues.  With abstol
          //         set to zero, the default value is used instead
          // 
          abstol = zero;
          // 
          //         Solve the symmetric eigenvalue problem
          // 
          F08.f08fb("Vectors", "Values in range", "Upper", n, a, vl, vu, il, iu, abstol, out m, w, z, jfail, out info);

          if (info < 0)
          {
              return;
          }


          // 
          if (info >= 0 && m > 0)
          {
            // 
            //            Print solution
            // 
            Console.WriteLine("  {0}{1,5}","Number of eigenvalues found =",m);
            Console.WriteLine("");
            Console.WriteLine(" {0}","Eigenvalues");
            for (j = 1 ; j <= m ; j++)
            {
              Console.Write(" {0, 10:f4}", w[j - 1]);
            }
            Console.WriteLine();
            // 
            X04.x04ca("General", "", n, m, z, "Selected eigenvectors", out ifail);
            if (info > 0)
            {
              Console.WriteLine("  {0}{1,5}","INFO eigenvectors failed to converge, INFO =",info);
              Console.WriteLine(" {0}","Indices of eigenvectors that did not converge");
              for (j = 1 ; j <= m ; j++)
              {
                Console.Write(" {0}", jfail[j - 1]);
              }
              Console.WriteLine();
            }
          }
          else if (m <= 0)
          {
            Console.WriteLine("  {0}{1,5}","M <= 0 =",m);
          }
          else
          {
            Console.WriteLine("  {0}{1,5}","Failure in F08.f08fb. info =",info);
          }
        }
        // 
      }
      catch (Exception e)
      {
        Console.WriteLine(e.Message);
        Console.WriteLine("Exception Raised");
      }
    }
  }
}