//      f08aa Example Program Text
//      C# version, NAG Copyright 2008
using System;
using NagLibrary;
using System.Globalization;
namespace NagDotNetExamples
{
  public class F08AAE
  {
    static string datafile = "ExampleData/f08aae.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 rnorm=0.0;
        int i,   info,   j,   ldb,   m,   n,   nrhs; 
        //      Skip heading in data file 
        sr.Reset();
        sr.Reset();
        m = int.Parse(sr.Next());
        n = int.Parse(sr.Next());
        nrhs = 1;
        double[,] a = new double[m, n];
        double[,] b = new double[Math.Max(m,n),nrhs];
        Console.WriteLine("f08aa Example Program Results");
        Console.WriteLine("");
        if (m > 0 && n > 0 && m >= n)
        {
          // 
          //         Read A and B from data file
          // 
          sr.Reset();
          for (i = 1 ; i <= m ; i++)
          {
            for (j = 1 ; j <= n ; j++)
            {
              a[i - 1 , j - 1] = double.Parse(sr.Next(), CultureInfo.InvariantCulture);
            }
          }
          sr.Reset();
          for (i = 1 ; i <= m ; i++)
          {
            b[i - 1,0] = double.Parse(sr.Next(), CultureInfo.InvariantCulture);
          }
          // 
          //         Solve the least squares problem min( norm2(b - Ax) ) for x
          // 
          ldb = (int)m;
          // 
          F08.f08aa("No transpose", m, n, nrhs, a, b, out info);
          // 
          //         Print solution
          // 

          if (info < 0)
          {
              return;
          }

            Console.WriteLine(" {0}","Least squares solution");
          for (i = 1 ; i <= n ; i++)
          {
            Console.Write(" {0, 11:f4}", b[i - 1,0]);
          }
          Console.WriteLine();
          // 
          //         Compute and print estimate of the square root of the residual
          //         sum of squares
          // 
          // Compute rnorm
          for (i = Math.Min(m,n); i < Math.Max(m,n); i++)
          {
            rnorm += b[i,0]*b[i,0];
          }
          rnorm = Math.Sqrt(rnorm);
          Console.WriteLine("");
          Console.WriteLine(" {0}","Square root of the residual sum of squares");
          Console.WriteLine("      {0,8:e2}",rnorm);

          
         
        }
        // 
      }
      catch (Exception e)
      {
        Console.WriteLine(e.Message);
        Console.WriteLine("Exception Raised");
      }
    }
  }
}