/* nag_dgbbrd (f08lec) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <nagf08.h>

int main(int argc, char *argv[])
{
  FILE          *fpin, *fpout;
  /* Scalars */
  Integer       i, j, kl, ku, m, n, ncc, pdab, pdc, pdq, pdpt;
  Integer       d_len, e_len;
  Integer       exit_status = 0;
  NagError      fail;
  Nag_OrderType order;
  /* Arrays */
  double        *ab = 0, *c = 0, *d = 0, *e = 0, *pt = 0, *q = 0;

#ifdef NAG_COLUMN_MAJOR
#define AB(I, J) ab[(J - 1) * pdab + ku + I - J]
  order = Nag_ColMajor;
#else
#define AB(I, J) ab[(I - 1) * pdab + kl + J - I]
  order = Nag_RowMajor;
#endif

  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_dgbbrd (f08lec) Example Program Results\n");

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n] ");
  fscanf(fpin, "%ld%ld%ld%ld%ld%*[^\n] ",
         &m, &n, &kl, &ku, &ncc);
#ifdef NAG_COLUMN_MAJOR
  pdab = kl + ku + 1;
  pdq = m;
  pdpt = n;
  pdc = m;
#else
  pdab = kl + ku + 1;
  pdq = m;
  pdpt = n;
  pdc = MAX(1, ncc);
#endif
  d_len = MIN(m, n);
  e_len = MIN(m, n) - 1;

  /* Allocate memory */
  if (!(ab = NAG_ALLOC((kl+ku+1) * m, double)) ||
      !(c = NAG_ALLOC(m * MAX(1, ncc), double)) ||
      !(d = NAG_ALLOC(d_len, double)) ||
      !(e = NAG_ALLOC(e_len, double)) ||
      !(pt = NAG_ALLOC(n * n, double)) ||
      !(q = NAG_ALLOC(m * m, double)))
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read A from data file */
  for (i = 1; i <= m; ++i)
    {
      for (j = MAX(1, i - kl); j <= MIN(n, i + ku); ++j)
        fscanf(fpin, "%lf", &AB(i, j));
    }
  fscanf(fpin, "%*[^\n] ");
  /* Reduce A to bidiagonal form */
  /* nag_dgbbrd (f08lec).
   * Reduction of real rectangular band matrix to upper
   * bidiagonal form
   */
  nag_dgbbrd(order, Nag_DoNotForm, m, n, ncc, kl, ku, ab,
             pdab, d, e, q, pdq, pt, pdpt, c, pdc, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_dgbbrd (f08lec).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print bidiagonal form */
  fprintf(fpout, "\nDiagonal\n");
  for (i = 1; i <= MIN(m, n); ++i)
    fprintf(fpout, "%9.4f%s", d[i-1], i%8 == 0?"\n":" ");
  if (m >= n)
    fprintf(fpout, "\nSuper-diagonal\n");
  else
    fprintf(fpout, "\nSub-diagonal\n");
  for (i = 1; i <= MIN(m, n) - 1; ++i)
    fprintf(fpout, "%9.4f%s", e[i-1], i%8 == 0?"\n":" ");
  fprintf(fpout, "\n");

 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (ab) NAG_FREE(ab);
  if (c) NAG_FREE(c);
  if (d) NAG_FREE(d);
  if (e) NAG_FREE(e);
  if (pt) NAG_FREE(pt);
  if (q) NAG_FREE(q);

  return exit_status;
}