/* nag_dpbequ (f07hfc) Example Program.
 *
 * Copyright 2004 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, scond, small;
  Integer       exit_status = 0, i, j, kd, kd1, kd2, n, pdab;

  /* Arrays */
  double        *ab = 0, *s = 0;
  char          nag_enum_arg[40];

  /* Nag Types */
  NagError      fail;
  Nag_UploType  uplo;
  Nag_OrderType order;

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

  INIT_FAIL(fail);

  printf("nag_dpbequ (f07hfc) Example Program Results\n\n");
  /* Skip heading in data file */
  scanf("%*[^\n]");

  scanf("%ld%ld%*[^\n]", &n, &kd);
  if (n < 0 || kd < 0)
    {
      printf("Invalid n or kd\n");
      exit_status = 1;
      goto END;
    }
  scanf(" %s%*[^\n]", nag_enum_arg);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg);

  pdab = kd+1;
  /* Allocate memory */
  if (!(ab = NAG_ALLOC((kd+1) * n, double)) ||
      !(s  = NAG_ALLOC(n, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }


  /* Read the upper or lower triangular part of the band matrix A
   * from data file.
   */
  if (uplo == Nag_Upper)
    {
      kd1 = 0;
      kd2 = kd;
      for (i = 1; i <= n; ++i)
	for (j = i; j <= MIN(n, i + kd); ++j) scanf("%lf", &AB_UPPER(i, j));
    }
  else
    {
      kd1 = kd;
      kd2 = 0;
      for (i = 1; i <= n; ++i)
	for (j = MAX(1, i - kd); j <= i; ++j) scanf("%lf", &AB_LOWER(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, kd1, kd2, 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 = 2;
      goto END;
    }
  printf("\n");

  /* Compute diagonal scaling factors using nag_dpbequ (f07hfc). */
  nag_dpbequ(order, uplo, n, kd, ab, pdab, s, &scond, &amax, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dpbequ (f07hfc).\n%s\n", fail.message);
      exit_status = 3;
      goto END;
    }
  /* Print scond, amax and the scale factors */
  printf("scond = %10.1e, amax = %10.1e\n", scond, amax);
  printf("\nDiagonal scaling factors\n");
  for (i = 0; i < n; ++i)
    printf("%11.1e%s", s[i], i%7 == 6?"\n":" ");
  printf("\n\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 (scond < 0.1 || amax < small || amax > big)
    {
      /* Scale A */
      if (uplo == Nag_Upper)
	for (j = 1; j <= n; ++j)
	  for (i = MAX(1, j - kd); i <= j; ++i)
	    AB_UPPER(i, j) *= s[i-1] * s[j-1];
      else
	for (j = 1; j <= n; ++j)
	  for (i = j; i <= MIN(n, j + kd); ++i)
	    AB_LOWER(i, j) *= s[i-1] * s[j-1];

      /* Print the scaled matrix using nag_band_real_mat_print (x04cec). */
      fflush(stdout);
      nag_band_real_mat_print(order, n, n, kd1, kd2, 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 = 4;
          goto END;
        }
    }
 END:
  if (ab) NAG_FREE(ab);
  if (s)  NAG_FREE(s);

  return exit_status;
}
#undef AB_UPPER
#undef AB_LOWER