/* nag_dpbrfs (f07hhc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

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

int main(void)
{
  /* Scalars */
  Integer       i, j, k, kd, n, nrhs, pdab, pdafb, pdb, pdx;
  Integer       ferr_len, berr_len;
  Integer       exit_status = 0;
  Nag_UploType  uplo;
  NagError      fail;
  Nag_OrderType order;
  /* Arrays */
  char          nag_enum_arg[40];
  double        *ab = 0, *afb = 0, *b = 0, *berr = 0, *ferr = 0, *x = 0;

#ifdef NAG_COLUMN_MAJOR
#define AB_UPPER(I, J)  ab[(J-1)*pdab + k + I - J - 1]
#define AB_LOWER(I, J)  ab[(J-1)*pdab + I - J]
#define AFB_UPPER(I, J) afb[(J-1)*pdafb + k + I - J - 1]
#define AFB_LOWER(I, J) afb[(J-1)*pdafb + I - J]
#define B(I, J)         b[(J-1)*pdb + I - 1]
#define X(I, J)         x[(J-1)*pdx + 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 + k + J - I - 1]
#define AFB_UPPER(I, J) afb[(I-1)*pdafb + J - I]
#define AFB_LOWER(I, J) afb[(I-1)*pdafb + k + J - I - 1]
#define B(I, J)         b[(I-1)*pdb + J - 1]
#define X(I, J)         x[(I-1)*pdx + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);

  printf("nag_dpbrfs (f07hhc) Example Program Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n] ");
  scanf("%ld%ld%ld%*[^\n] ", &n, &kd, &nrhs);
  pdab = kd + 1;
  pdafb = kd + 1;
#ifdef NAG_COLUMN_MAJOR
  pdb = n;
  pdx = n;
#else
  pdb = nrhs;
  pdx = nrhs;
#endif


  ferr_len = nrhs;
  berr_len = nrhs;

  /* Allocate memory */
  if (!(berr = NAG_ALLOC(berr_len, double)) ||
      !(ferr = NAG_ALLOC(ferr_len, double)) ||
      !(ab = NAG_ALLOC((kd+1) * n, double)) ||
      !(afb = NAG_ALLOC((kd+1) * n, double)) ||
      !(b = NAG_ALLOC(n * nrhs, double)) ||
      !(x = NAG_ALLOC(n * nrhs, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read A from data file */
  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);

  k = kd + 1;
  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= MIN(i+kd, n); ++j)
            scanf("%lf", &AB_UPPER(i, j));
        }
      scanf("%*[^\n] ");
    }
  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] ");
  /* Copy A to AF and B to X */
  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= MIN(i+kd, n); ++j)
            AFB_UPPER(i, j) = AB_UPPER(i, j);
        }
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = MAX(1, i-kd); j <= i; ++j)
            AFB_LOWER(i, j) = AB_LOWER(i, j);
        }
    }
  for (i = 1; i <= n; ++i)
    {
      for (j = 1; j <= nrhs; ++j)
        X(i, j) = B(i, j);
    }
  /* Factorize A in the array AFP */
  /* nag_dpbtrf (f07hdc).
   * Cholesky factorization of real symmetric
   * positive-definite band matrix
   */
  nag_dpbtrf(order, uplo, n, kd, afb, pdafb, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dpbtrf (f07hdc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Compute solution in the array X */
  /* nag_dpbtrs (f07hec).
   * Solution of real symmetric positive-definite band system
   * of linear equations, multiple right-hand sides, matrix
   * already factorized by nag_dpbtrf (f07hdc)
   */
  nag_dpbtrs(order, uplo, n, kd, nrhs, afb, pdafb, x, pdx, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dpbtrs (f07hec).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Improve solution, and compute backward errors and */
  /* estimated bounds on the forward errors */
  /* nag_dpbrfs (f07hhc).
   * Refined solution with error bounds of real symmetric
   * positive-definite band system of linear equations,
   * multiple right-hand sides
   */
  nag_dpbrfs(order, uplo, n, kd, nrhs, ab, pdab, afb, pdafb,
             b, pdb, x, pdx, ferr, berr, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dpbrfs (f07hhc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print details of solution */

  /* nag_gen_real_mat_print (x04cac).
   * Print real general matrix (easy-to-use)
   */
  fflush(stdout);
  nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs, x,
                         pdx, "Solution(s)", 0, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_gen_real_mat_print (x04cac).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }
  printf("\nBackward errors (machine-dependent)\n");
  for (j = 1; j <= nrhs; ++j)
    printf("%11.1e%s", berr[j-1], j%7 == 0?"\n":" ");
  printf("\nEstimated forward error bounds (machine-dependent)\n");
  for (j = 1; j <= nrhs; ++j)
    printf("%11.1e%s", ferr[j-1], j%7 == 0?"\n":" ");
  printf("\n");
 END:
  if (berr) NAG_FREE(berr);
  if (ferr) NAG_FREE(ferr);
  if (ab) NAG_FREE(ab);
  if (afb) NAG_FREE(afb);
  if (b) NAG_FREE(b);
  if (x) NAG_FREE(x);
  return exit_status;
}