/* nag_dspr (f16pqc) Example Program.
 *
 * Copyright 2005 Numerical Algorithms Group.
 *
 * Mark 8, 2005.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf16.h>
#include <nagx04.h>

int main(void)
{

  /* Scalars */
  double alpha, beta;
  Integer ap_len, exit_status, i, incx, j, n, xlen;

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

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

#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

  exit_status = 0;
  INIT_FAIL(fail);

  Vprintf( "nag_dspr (f16pqc) Example Program Results\n\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");

  /* Read the problem dimension */
  Vscanf("%ld%*[^\n] ", &n);

  /* Read the uplo storage parameter */
  Vscanf("%s%*[^\n] ", nag_enum_arg);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  uplo = nag_enum_name_to_value(nag_enum_arg);

  /* Read scalar parameters */
  Vscanf("%lf%lf%*[^\n] ", &alpha, &beta);
  /* Read increment parameter */
  Vscanf("%ld%*[^\n] ", &incx);

  ap_len = n*(n+1)/2;
  xlen = MAX(1, 1 + (n - 1)*ABS(incx));

  if (n > 0)
    {

      /* Allocate memory */
      if ( !(ap = NAG_ALLOC(ap_len, double)) ||
           !(x = NAG_ALLOC(xlen, double)))
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
    }
  else
    {
      Vprintf("Invalid n\n");
      exit_status = 1;
      return exit_status;
    }

  /* Input matrix A and vector x */

  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= n; ++j)
            Vscanf("%lf", &A_UPPER(i,j));
          Vscanf("%*[^\n] ");
        }
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = 1; j <= i; ++j)
            Vscanf("%lf", &A_LOWER(i,j));
          Vscanf("%*[^\n] ");
        }
    }
  for (i = 0; i < xlen; ++i)
    Vscanf("%lf%*[^\n] ", &x[i]);

  /* nag_dspr(f16pqc).
   * Rank one update of real symmetric matrix,
   * packed storage.
   */
  nag_dspr(order, uplo, n, alpha, x, incx, beta, ap, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_dspr.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print updated matrix A */
  /* nag_pack_real_mat_print (x04ccc).
   * Print real packed triangular matrix (easy-to-use)
   */
  nag_pack_real_mat_print(order, uplo, Nag_NonUnitDiag, n, ap,
                          "Updated Matrix A", 0, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_pack_real_mat_print (x04ccc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

 END:
  if (ap) NAG_FREE(ap);
  if (x) NAG_FREE(x);

  return exit_status;
}