/* nag_sparse_sym_sol (f11jec) Example Program.
 *
 * Copyright 1998 Numerical Algorithms Group.
 *
 * Mark 5, 1998.
 *
 */

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

int main(void)
{
  double                 *a = 0, *b = 0, *x = 0;
  double                 omega;
  double                 rnorm;
  double                 tol;
  Integer                exit_status = 0;
  Integer                *icol, *irow;
  Integer                i, n, maxitn, itn, nnz;
  char                   nag_enum_arg[40];
  Nag_SparseSym_Method   method;
  Nag_SparseSym_PrecType precon;
  Nag_Sparse_Comm        comm;
  NagError               fail;

  INIT_FAIL(fail);

  printf("nag_sparse_sym_sol (f11jec) Example Program Results\n");

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

  /* Read algorithmic parameters */
  scanf("%ld%*[^\n]", &n);
  scanf("%ld%*[^\n]", &nnz);

  scanf("%s", nag_enum_arg);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  method = (Nag_SparseSym_Method) nag_enum_name_to_value(nag_enum_arg);
  scanf("%s%*[^\n]", nag_enum_arg);
  precon = (Nag_SparseSym_PrecType) nag_enum_name_to_value(nag_enum_arg);

  scanf("%lf%*[^\n]", &omega);
  scanf("%lf%ld%*[^\n]", &tol, &maxitn);

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

  /* Read the matrix a */
  for (i = 1; i <= nnz; ++i)
    scanf("%lf%ld%ld%*[^\n]", &a[i-1], &irow[i-1], &icol[i-1]);

  /* Read right-hand side vector b and initial approximate solution x */
  for (i = 1; i <= n; ++i)
    scanf("%lf", &b[i-1]);
  scanf(" %*[^\n]");

  for (i = 1; i <= n; ++i)
    scanf("%lf", &x[i-1]);
  scanf(" %*[^\n]");

  /* Solve Ax = b  */
  /* nag_sparse_sym_sol (f11jec).
   * Solver with Jacobi, SSOR, or no preconditioning
   * (symmetric)
   */
  nag_sparse_sym_sol(method, precon, n, nnz, a, irow, icol, omega, b, tol,
                     maxitn, x, &rnorm, &itn, &comm, &fail);

  printf(" %s%10ld%s\n", "Converged in", itn, " iterations");
  printf(" %s%16.3e\n", "Final residual norm =", rnorm);

  /* Output x */
  for (i = 1; i <= n; ++i)
    printf(" %16.4e\n", x[i-1]);

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

  return exit_status;
}