/* nag_dsymv (f16pcc) 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 exit_status, i, incx, incy, j, n, pda, xlen, ylen;

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

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

#ifdef NAG_COLUMN_MAJOR
#define A(I,J) a[(J-1)*pda + I - 1]
  order = Nag_ColMajor;
#else
#define A(I,J) a[(I-1)*pda + J - 1]
  order = Nag_RowMajor;
#endif

  exit_status = 0;
  INIT_FAIL(fail);
  Vprintf( "nag_dsymv (f16pcc) Example Program Results\n\n");

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

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

  /* Read uplo */
  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 parameters */
  Vscanf("%ld%ld%*[^\n] ", &incx, &incy);

  pda = n;
  xlen = MAX(1, 1 + (n - 1)*ABS(incx));
  ylen = MAX(1, 1 + (n - 1)*ABS(incy));

  if (n > 0)
    {
      /* Allocate memory */
      if ( !(a = NAG_ALLOC(n*pda, double)) ||
           !(x = NAG_ALLOC(xlen, double)) ||
           !(y = NAG_ALLOC(ylen, double)) )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
    }
  else
    {
      Vprintf("Invalid n\n");
      exit_status = 1;
      return exit_status;
    }

  /* Input the matrix A and vectors x and y */

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

  /* nag_dsymv(f16pcc).
   * Symmetric matrix-vector multiply.
   *
   */
  nag_dsymv(order, uplo, n, alpha, a, pda, x, incx, beta,
            y, incy, &fail );
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_dsymv.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print output vector y */
  Vprintf("%s\n", "  y");
  for (i = 1; i <= ylen; ++i)
    {
      Vprintf("%11f\n", y[i-1]);
    }

 END:
  if (a) NAG_FREE(a);
  if (x) NAG_FREE(x);
  if (y) NAG_FREE(y);

  return exit_status;
}