/* nag_sparse_sym_matvec (f11xec) Example Program.
 *
 * Copyright 2011, Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

#include <nag.h>
#include <nag_stdlib.h>
#include <nagf11.h>

int main(void)
{
  /* Scalars */
  Integer                 exit_status = 0;
  Integer                 i, j, n, nnz;
  /* Arrays */
  char                    nag_enum_arg[40];
  Integer                 *irow = 0, *icol = 0;
  double                  *a = 0, *x = 0, *y = 0;
  /* NAG types */
  NagError                fail;
  Nag_SparseSym_CheckData check;

  INIT_FAIL(fail);

  printf("nag_sparse_sym_matvec (f11xec) Example Program Results\n");

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

  /* Read order of matrix and number of non-zero entries */
  scanf("%ld%*[^\n]", &n);
  scanf("%ld%*[^\n]", &nnz);

  /* Allocate memory */
  if ( !(a = NAG_ALLOC(nnz, double)) ||
       !(x = NAG_ALLOC(n, double)) ||
       !(y = NAG_ALLOC(n, double)) ||
       !(icol = NAG_ALLOC(nnz, Integer)) ||
       !(irow = NAG_ALLOC(nnz, Integer)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Read the matrix A */
  for (i = 0; i < nnz; i++)
    scanf("%lf""%ld%ld%*[^\n]", &a[i], &irow[i], &icol[i]);

  /* Read the vector x */
  for (j = 0; j < n; j++)
    scanf("%lf", &x[j]);
  scanf("%*[^\n]");

  /* Set matrix to be checked */
  scanf("%s%*[^\n]", nag_enum_arg);   /* Nag_SparseSym_Check */
  check = (Nag_SparseSym_CheckData) nag_enum_name_to_value (nag_enum_arg);

  /* nag_sparse_sym_matvec (f11xec)
   * Real sparse symmetric matrix vector multiply.
   */
  nag_sparse_sym_matvec(n, nnz, a, irow, icol, check, x, y, &fail);

  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_sparse_sym_matvec (f11xec)\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  /* Output results */
  printf(" Matrix-vector product\n");
  for (j = 0; j < n; j++)
    printf("%16.4e\n", y[j]);

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

  return exit_status;
}