/* nag_sparse_herm_sol (f11jsc) Example Program.
 *
 * Copyright 2011, Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

#include <nag.h>
#include <nag_stdlib.h>
#include <naga02.h>
#include <nagf11.h>

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

  INIT_FAIL(fail);

  printf("nag_sparse_herm_sol (f11jsc) Example Program Results\n");
  /* Skip heading in data file*/
  scanf("%*[^\n]");
  /* Read algorithmic parameters*/
  scanf("%ld%*[^\n]", &n);
  scanf("%ld%*[^\n]", &nnz);
  scanf("%s%*[^\n]", 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 */
  if (
      !(a = NAG_ALLOC((nnz), Complex)) ||
      !(b = NAG_ALLOC((n), Complex)) ||
      !(x = NAG_ALLOC((n), Complex)) ||
      !(rdiag = 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 , %lf ) %ld%ld%*[^\n] ",
          &a[i].re, &a[i].im, &irow[i], &icol[i]);
  /* Read rhs vector b and initial approximate solution x*/
  for (i = 0; i < n; i++)
    scanf(" ( %lf , %lf ) ", &b[i].re, &b[i].im);
  scanf("%*[^\n]");
  for (i = 0; i < n; i++)
    scanf(" ( %lf , %lf ) ", &x[i].re, &x[i].im);
  scanf("%*[^\n]");

  /* nag_sparse_herm_sol (f11jsc).
   * Solution of complex sparse Hermitian linear system, conjugate
   * gradient/Lanczos method, Jacobi or SSOR preconditioner
   */
  nag_sparse_herm_sol(method, precon, n, nnz, a, irow, icol, omega,
		      b, tol, maxitn, x, &rnorm, &itn, rdiag, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_sparse_herm_sol (f11jsc)\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
  printf("Converged in  %10ld  iterations \n", itn);
  printf("Final residual norm = %10.3e\n", rnorm);

  /* Output x*/
  printf("\n     Converged Solution\n");
  for (i = 0; i < n; i++)
    printf("(%11.4e, %11.4e)\n", x[i].re, x[i].im);

 END:
  if (a) NAG_FREE(a);
  if (b) NAG_FREE(b);
  if (x) NAG_FREE(x);
  if (rdiag) NAG_FREE(rdiag);
  if (icol) NAG_FREE(icol);
  if (irow) NAG_FREE(irow);
  return exit_status;
}