/* nag_dpbsvx (f07hbc) 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>

int main(void)
{

  /* Scalars */
  double                rcond;
  Integer               exit_status = 0;
  Integer               i, j, kd, n, nrhs, pdab, pdafb, pdb, pdx;

  /* Arrays */
  double                *ab = 0, *afb = 0, *b = 0, *berr = 0, *ferr = 0;
  double                *s = 0, *x = 0;
  char                  nag_enum_arg[40];

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

#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]
#define B(I, J)        b[(J-1)*pdb + I - 1]
  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]
#define B(I, J)        b[(I-1)*pdb + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);

  printf("nag_dpbsvx (f07hbc) Example Program Results\n\n");
  /* Skip heading in data file */
  scanf("%*[^\n]");

  scanf("%ld%ld%ld%*[^\n]", &n, &kd, &nrhs);
  if (n < 0 || nrhs < 0 || kd < 0)
    {
      printf("Invalid n, kd or nrhs\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);

  /* Allocate memory */
  if (!(ab   = NAG_ALLOC((kd+1) * n, double)) ||
      !(afb  = NAG_ALLOC((kd+1) * n, double)) ||
      !(b    = NAG_ALLOC(n * nrhs, double)) ||
      !(berr = NAG_ALLOC(nrhs, double)) ||
      !(ferr = NAG_ALLOC(nrhs, double)) ||
      !(s    = NAG_ALLOC(n, double)) ||
      !(x    = NAG_ALLOC(n * nrhs, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
    
  pdab = kd+1;
  pdafb = kd+1;
#ifdef NAG_COLUMN_MAJOR
  pdb = n;
  pdx = n;
#else
  pdb = nrhs;
  pdx = nrhs;
#endif

  /* Read the upper or lower triangular part of the band matrix A from
   * data file.
   */
  if (uplo == Nag_Upper)
    for (i = 1; i <= n; ++i)
      for (j = i; j <= MIN(n, i + kd); ++j) scanf("%lf", &AB_UPPER(i, j));
  else
    for (i = 1; i <= n; ++i)
      for (j = MAX(1, i - kd); j <= i; ++j) scanf("%lf", &AB_LOWER(i, j));
  scanf("%*[^\n]");

  /* Read B from data file */
  for (i = 1; i <= n; ++i)
    for (j = 1; j <= nrhs; ++j) scanf("%lf", &B(i, j));
  scanf("%*[^\n]");

  /* Solve the equations AX = B for X using nag_dpbsvx (f07hbc). */
  fflush(stdout);
  nag_dpbsvx(order, Nag_EquilibrateAndFactor, uplo, n, kd, nrhs, ab, pdab, afb,
             pdafb, &equed, s, b, pdb, x, pdx, &rcond, ferr, berr, &fail);
  if (fail.code != NE_NOERROR && fail.code != NE_SINGULAR)
    {
      printf("Error from nag_dpbsvx (f07hbc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print solution using nag_gen_real_mat_print (x04cac). */
   nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs,
                         x, pdx, "Solution(s)", 0, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("\nError from nag_gen_real_mat_print (x04cac).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print error bounds, condition number and the form of equilibration */
  printf("\nBackward errors (machine-dependent)\n");
  for (j = 0; j < nrhs; ++j) printf("%11.1e%s", berr[j], j%7 == 6?"\n":" ");

  printf("\n\nEstimated forward error bounds (machine-dependent)\n");
  for (j = 0; j < nrhs; ++j) printf("%11.1e%s", ferr[j], j%7 == 6?"\n":" ");

  printf("\n\nEstimate of reciprocal condition number\n%11.1e\n\n", rcond);
  if (equed == Nag_NoEquilibration)
    printf("A has not been equilibrated\n");
  else if (equed == Nag_RowAndColumnEquilibration)
    printf("A has been row and column scaled as diag(S)*A*diag(S)\n");
  if (fail.code == NE_SINGULAR)
    {
      printf("Error from nag_dpbsvx (f07hbc).\n%s\n", fail.message);
      exit_status = 1;
    }
 END:
  if (ab)   NAG_FREE(ab);
  if (afb)  NAG_FREE(afb);
  if (b)    NAG_FREE(b);
  if (berr) NAG_FREE(berr);
  if (ferr) NAG_FREE(ferr);
  if (s)    NAG_FREE(s);
  if (x)    NAG_FREE(x);

  return exit_status;
}

#undef AB_UPPER
#undef AB_LOWER
#undef B