//      d01al Example Program Text
//      C# version, NAG Copyright 2008
using System;
using NagLibrary;
using System.Globalization;
namespace NagDotNetExamples
{
  public class D01ALE
  {
    static void Main(String[] args)
    {
      StartExample();
    }
    public static int kount = 0;
    public static void StartExample()
    {
      try
      {
        const int npts = 1;
        const int lw = 800;
        D01.D01AL_F fD01AL = new D01.D01AL_F(f);
        double a,  abserr,  b,  epsabs,  epsrel,  result; double[] points = new double[1];
        double[] w = new double[lw];
        int subintvls;
        int ifail;
        Console.WriteLine("d01al Example Program Results");
        epsabs = 0.00e0;
        epsrel = 1.00e-03;
        a = 0.00e0;
        b = 1.00e0;
        points[0] = 1.00e0 / 7.00e0;
        kount = 0;
        // 
        D01.d01al(fD01AL, a, b, npts, points, epsabs, epsrel, out result, out abserr, w,
                  out subintvls, out ifail);
        // 
        if (ifail >= 0)
        {
          Console.WriteLine("");
          Console.WriteLine("  {0}{1,10:f4}", "a      - lower limit of integration = ", a);
          Console.WriteLine("  {0}{1,10:f4}", "b      - upper limit of integration = ", b);
          Console.WriteLine("  {0}{1,9:e2}", "epsabs - absolute accuracy requested = ", epsabs);
          Console.WriteLine("  {0}{1,9:e2}", "epsrel - relative accuracy requested = ", epsrel);
          Console.WriteLine("  {0}{1,10:f4}", "points[0] - given break-point = ",
          points[0]);
          Console.WriteLine("");
          if (ifail != 0)
          {
            Console.WriteLine("  {0}{1,4}", "ifail = ", ifail);
          }
          if (ifail <= 5)
          {
            Console.WriteLine("  {0}{1,9:f5}", "  result - approximation to the integral = ", result);
            Console.WriteLine("  {0}{1,9:e2}", "  abserr - estimate of the absolute error = ", abserr);
            Console.WriteLine("  {0}{1,4}", "  kount  - number of function evaluations = ", kount);
            Console.WriteLine("  {0}{1,4}", "  subintvls  - number of subintervals used = ", subintvls);
          }
        }
        else
        {
          Console.WriteLine("");
          Console.WriteLine("** d01al failed with ifail = {0,5}", ifail);
        }
        // 
      }
      catch (Exception e)
      {
        Console.WriteLine(e.Message);
        Console.WriteLine("Exception Raised");
      }
      ;
    }
    //  
    public static double f(double x)
    {
      double fValue;
      double a;
      kount = kount + 1;
      a = Math.Abs(x - 1.00e0 / 7.00e0);
      fValue = 0.00e0;
      if (a != 0.00e0)
      {
        fValue = Math.Pow(a, (-0.50e0));
      }
      return fValue;
    }
  }
}