/* nag_dpptrf (f07gdc) 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       ap_len, i, j, n;
  Integer       exit_status = 0;
  Nag_UploType  uplo;
  NagError      fail;
  Nag_OrderType order;

  /* Arrays */
  char          nag_enum_arg[40];
  double        *ap = 0;

#ifdef NAG_COLUMN_MAJOR
#define A_UPPER(I, J) ap[J*(J-1)/2 + I - 1]
#define A_LOWER(I, J) ap[(2*n-J)*(J-1)/2 + I - 1]
  order = Nag_ColMajor;
#else
#define A_LOWER(I, J) ap[I*(I-1)/2 + J - 1]
#define A_UPPER(I, J) ap[(2*n-I)*(I-1)/2 + J - 1]
  order = Nag_RowMajor;
#endif

  INIT_FAIL(fail);

  printf("nag_dpptrf (f07gdc) Example Program Results\n\n");

  /* Skip heading in data file */
  scanf("%*[^\n] ");
  scanf("%ld%*[^\n] ", &n);
  ap_len = n*(n+1)/2;

  /* Allocate memory */
  if (!(ap = NAG_ALLOC(ap_len, 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);

  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= n; ++j)
            scanf("%lf", &A_UPPER(i, j));
        }
      scanf("%*[^\n] ");
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = 1; j <= i; ++j)
            scanf("%lf", &A_LOWER(i, j));
        }
      scanf("%*[^\n] ");
    }
  /* Factorize A */
  /* nag_dpptrf (f07gdc).
   * Cholesky factorization of real symmetric
   * positive-definite matrix, packed storage
   */
  nag_dpptrf(order, uplo, n, ap, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_dpptrf (f07gdc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Print factor */
  /* nag_pack_real_mat_print (x04ccc).
   * Print real packed triangular matrix (easy-to-use)
   */
  fflush(stdout);
  nag_pack_real_mat_print(order, uplo, Nag_NonUnitDiag, n, ap,
                          "Factor", 0, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_pack_real_mat_print (x04ccc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

 END:
  if (ap) NAG_FREE(ap);
  return exit_status;
}