/* nag_dpbsv (f07hac) 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 */
  Integer       exit_status = 0, i, j, kd, n, nrhs, pdb, pdab;

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

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

#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_dpbsv (f07hac) 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)) ||
      !(b =  NAG_ALLOC(n*nrhs, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  pdab = kd + 1;
#ifdef NAG_COLUMN_MAJOR
  pdb = n;
#else
  pdb = 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_dpbsv (f07hac). */
  nag_dpbsv(order, uplo, n, kd, nrhs, ab, pdab, b, pdb, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dpbsv (f07hac).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print solution */
  printf("Solution\n");
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= nrhs; ++j)
	printf("%11.4f%s", B(i, j), j%7 == 0?"\n":" ");
      printf("\n");
    }

  /* Print details of factorization */
  printf("\n");
  fflush(stdout);
  if (uplo == Nag_Upper)
    nag_band_real_mat_print(order, n, n, 0, kd, ab, pdab, "Cholesky factor U",
			    0, &fail);
  else
    nag_band_real_mat_print(order, n, n, kd, 0, ab, pdab, "Cholesky factor L",
			    0, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_band_real_mat_print (x04cec).\n%s\n",
	     fail.message);
      exit_status = 1;
    }
 END:
  if (ab) NAG_FREE(ab);
  if (b)  NAG_FREE(b);

  return exit_status;
}
#undef AB_LOWER
#undef AB_UPPER
#undef B