/* nag_real_eigensystem_sel(f02ecc) Example Program.
 *
 * Copyright 1998 Numerical Algorithms Group.
 *
 * Mark 5, 1998.
 *
 */

#include <nag.h>
#include <nag_stdlib.h>
#include <stdio.h>
#include <nagf02.h>

#define NMAX 8
#define MMAX 3
#define TDA NMAX
#define TDV MMAX

int main(void)
{

  double a[NMAX][NMAX];
  double wl, wu;

  Integer i, j, m, n;
  Integer mest = MMAX;
  Integer tda=TDA, tdv=TDV;

  Complex w[NMAX], v[NMAX][MMAX];

  Vprintf("f02ecc Example Program Results\n\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n]");

  Vscanf("%ld%lf%lf%*[^\n]",&n, &wl, &wu);

  if (n <= NMAX)
    {
      /* Read a from data file */
      for (i = 0; i < n; ++i)
        for (j = 0; j < n; ++j)
          Vscanf("%lf",&a[i][j]);
      Vscanf("%*[^\n]");

      /* Compute selected eigenvalues and eigenvectors of A */

      f02ecc(Nag_Select_Modulus, n, &a[0][0], tda, wl, wu, mest, &m, w,
             &v[0][0], tdv, NAGERR_DEFAULT);

      Vprintf("\n\nEigenvalues\n");
      for (i = 0; i < m; ++i)
        Vprintf("(%7.4f, %7.4f)  ", w[i].re, w[i].im);
      Vprintf("\n");


      Vprintf(" Eigenvectors\n    ");
      for (i = 1; i <= m; i++)
        Vprintf("%15ld%s", i, i%m == 0 ?"\n" : "");
      for (i = 0; i < n; i++)
        {
          Vprintf("%ld  ", i + 1);
          for (j = 0; j < m; j++)
            Vprintf("(%8.4f, %8.4f)%s", v[i][j].re,
                    v[i][j].im, (j + 1) % m == 0 ? "\n":"  ");
        }
      return EXIT_SUCCESS;
    }
  else
    {
      Vprintf( "Incorrect input value of n.\n");
      return EXIT_FAILURE;
    }
}