/* nag_dgbequ (f07bfc) Example Program.
 *
 * Copyright 2011 Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <nagf07.h>
#include <nagx02.h>

int main(void)
{

  /* Scalars */
  double        amax, big, colcnd, rowcnd, small;
  Integer       exit_status = 0, i, j, kl, ku, n, pdab;

  /* Arrays */
  double        *ab = 0, *c = 0, *r = 0;

  /* Nag Types */
  NagError      fail;
  Nag_OrderType order;
  Nag_Boolean   scaled = Nag_FALSE;

#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);

  printf("nag_dgbequ (f07bfc) Example Program Results\n\n");

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

  scanf("%ld%ld%ld%*[^\n] ", &n, &kl, &ku);
  if (n < 0 || kl < 0 || ku < 0)
    {
      printf("Invalid n or kl or ku\n");
      exit_status = 1;
      goto END;
    }
  /* Allocate arrays */
  pdab = kl+ku+1;
  if (!(ab = NAG_ALLOC(pdab * n, double)) ||
      !(c = NAG_ALLOC(n, double)) ||
      !(r = NAG_ALLOC(n, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read the band matrix A from data file */
  for (i = 1; i <= n; ++i)
    for (j = MAX(i - kl, 1); j <= MIN(i + ku, n); ++j)
      scanf("%lf", &AB(i, j));
  scanf("%*[^\n]");

  /* Print the matrix A using nag_band_real_mat_print (x04cec). */
  fflush(stdout);
  nag_band_real_mat_print(order, n, n, kl, ku, ab, pdab, "Matrix A", 0, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_band_real_mat_print (x04cec).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  printf("\n");
  /* Compute row and column scaling factors using nag_dgbequ (f07bfc). */
  nag_dgbequ(order, n, n, kl, ku, ab, pdab, r, c, &rowcnd, &colcnd, &amax,
             &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dgbequ (f07bfc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print rowcnd, colcnd, amax and the scale factors */
  printf("rowcnd = %10.1e, colcnd = %10.1e, amax = %10.1e\n\n", rowcnd,
          colcnd, amax);
  printf("Row scale factors\n");
  for (i = 1; i <= n; ++i) printf("%11.1e%s", r[i-1], i%7 == 0?"\n":" ");

  printf("\n\nColumn scale factors\n");
  for (i = 1; i <= n; ++i) printf("%11.1e%s", c[i-1], i%7 == 0?"\n":" ");

  /* Compute values close to underflow and overflow using 
   * nag_real_safe_small_number (x02amc), nag_machine_precision (x02ajc) and
   * nag_real_base (x02bhc)
   */
  small = nag_real_safe_small_number /  nag_machine_precision * nag_real_base;
  big = 1.0 / small;
  if (colcnd < 0.1)
    {
      scaled = Nag_TRUE;
      /* column scale A */
      for (j = 1; j <= n; ++j)
	for (i = MAX(1, j - ku); i <= MIN(n, j + kl); ++i)
	  AB(i, j) *= c[j - 1];
    }
  if (rowcnd < 0.1 || amax < small || amax > big)
    {
      /* row scale A */
      scaled = Nag_TRUE;
      for (j = 1; j <= n; ++j)
	for (i = MAX(1, j - ku); i <= MIN(n, j + kl); ++i)
	  AB(i, j) *= r[i-1];
    }
  if (scaled)
    {
      /* Print the row and column scaled matrix using 
       * nag_band_real_mat_print (x04cec).
       */
      fflush(stdout);
      printf("\n\n");
      nag_band_real_mat_print(order, n, n, kl, ku, ab, pdab, "Scaled matrix",
			      0, &fail);
      if (fail.code != NE_NOERROR)
        {
          printf("Error from nag_band_real_mat_print (x04cec).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
    }
 END:
  if (ab) NAG_FREE(ab);
  if (c) NAG_FREE(c);
  if (r) NAG_FREE(r);

  return exit_status;
}