/* nag_complex_eigensystem_sel (f02gcc) Example Program.
 *
 * Copyright 1998 Numerical Algorithms Group.
 *
 * Mark 5, 1998.
 * Mark 8 revised, 2004.
 *
 */

#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <stdio.h>
#include <nagf02.h>

#define MMAX 3

#define A(I, J) a[(I) *tda + J]
#define V(I, J) v[(I) *tdv + J]

int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;

  Complex  *a = 0, *v = 0, *w = 0;
  Integer  exit_status = 0, i, j, m, mest = MMAX, n, tda, tdv;
  NagError fail;
  double   wl, wu;

  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);

  fprintf(fpout,
          "nag_complex_eigensystem_sel (f02gcc) Example Program Results\n");

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

  fscanf(fpin, "%ld%lf%lf%*[^\n] ", &n, &wl, &wu);
  if (n >= 0)
    {
      if (!(a = NAG_ALLOC(n*n, Complex)) ||
          !(v = NAG_ALLOC(n*mest, Complex)) ||
          !(w = NAG_ALLOC(n, Complex)))
        {
          fprintf(fpout, "Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tda = n;
      tdv = mest;
    }
  else
    {
      fprintf(fpout, "Invalid n.\n");
      exit_status = 1;
      return exit_status;
    }

  /* Read a from data file */
  for (i = 0; i < n; ++i)
    for (j = 0; j < n; ++j)
      fscanf(fpin, " ( %lf, %lf ) ", &A(i, j).re, &A(i, j).im);

  /* Compute selected eigenvalues and eigenvectors of A */

  /* nag_complex_eigensystem_sel (f02gcc).
   * Computes selected eigenvalues and eigenvectors of a
   * complex general matrix
   */
  nag_complex_eigensystem_sel(Nag_Select_Modulus, n, a, tda, wl, wu, mest, &m,
                              w, v, tdv, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_complex_eigensystem_sel (f02gcc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  fprintf(fpout, "\n\nEigenvalues\n\n");
  for (i = 0; i < m; ++i)
    fprintf(fpout, "(%7.4f, %7.4f)%s", w[i].re, w[i].im, (i+1)%2 == 0?"\n":" ");

  fprintf(fpout, "\nEigenvectors\n");
  for (i = 1; i <= m; i++)
    fprintf(fpout, "%15ld%s", i, i%m == 0?"\n":"");

  for (i = 0; i < n; i++)
    {
      fprintf(fpout, "%ld  ", i + 1);
      for (j = 0; j < m; j++)
        fprintf(fpout, "(%8.4f, %8.4f)%s", V(i, j).re,
                V(i, j).im, (j + 1)%m == 0?"\n":"  ");
    }
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (a) NAG_FREE(a);
  if (v) NAG_FREE(v);
  if (w) NAG_FREE(w);
  return exit_status;
}