/* nag_sparse_herm_chol_sol (f11jqc) 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                dscale, dtol, rnorm, tol;
  Integer               i, itn, la, lfill, maxitn, n, nnz, nnzc, npivm;
  /* Arrays */
  char                  nag_enum_arg[40];
  Complex               *a = 0, *b = 0, *x = 0;
  Integer               *icol = 0, *ipiv = 0, *irow = 0, *istr = 0;
  /* NAG types */
  Nag_SparseSym_Method  method;
  Nag_SparseSym_Piv     pstrat;
  Nag_SparseSym_Fact    mic;
  NagError              fail;

  INIT_FAIL(fail);

  printf("nag_sparse_herm_chol_sol (f11jqc) Example Program Results\n\n");
  /* Skip heading in data file*/
  scanf("%*[^\n]");
  /* Read algorithmic parameters*/
  scanf("%ld%*[^\n]", &n);
  scanf("%ld%*[^\n]", &nnz);

  /* Allocate memory */
  la = 3 * nnz;
  if (
      !(a = NAG_ALLOC(la, Complex)) ||
      !(b = NAG_ALLOC(n, Complex)) ||
      !(x = NAG_ALLOC(n, Complex)) ||
      !(icol = NAG_ALLOC(la, Integer)) ||
      !(ipiv = NAG_ALLOC(n, Integer)) ||
      !(irow = NAG_ALLOC(la, Integer)) ||
      !(istr = NAG_ALLOC(n + 1, Integer))
      )
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  scanf("%s%*[^\n]", nag_enum_arg);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  method = (Nag_SparseNsym_Method) nag_enum_name_to_value(nag_enum_arg);
  scanf("%"NAG_IFMT "%lf%*[^\n]", &lfill, &dtol);
  scanf("%s%*[^\n]", nag_enum_arg);
  mic = (Nag_SparseSym_Fact)  nag_enum_name_to_value(nag_enum_arg);
  scanf("%lf%*[^\n]", &dscale);
  scanf("%s%*[^\n]", nag_enum_arg);
  pstrat = (Nag_SparseNsym_Piv) nag_enum_name_to_value(nag_enum_arg);
  scanf("%lf%ld%*[^\n]", &tol, &maxitn);

  /* 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);

  /* Calculate incomplete Cholesky factorization of complex sparse Hermitian
   * matrix using nag_sparse_herm_chol_fac (f11jnc).
   */
  nag_sparse_herm_chol_fac(n, nnz, a, la, irow, icol, lfill, dtol, mic,
			   dscale, pstrat, ipiv, istr, &nnzc, &npivm,
			   &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_sparse_herm_chol_fac (f11jnc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
  /* Solve Linear System. */
  /* nag_sparse_herm_chol_sol (f11jqc).
   * Solution of complex sparse Hermitian linear system, conjugate
   * gradient/Lanczos method, preconditioner computed by f11jnc
   */
  nag_sparse_herm_chol_sol(method, n, nnz, a, la, irow, icol, ipiv, istr,
			   b, tol, maxitn, x, &rnorm, &itn, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_sparse_herm_chol_sol.(f11jqc)\n%s\n",
             fail.message);
      exit_status = 2;
      goto END;
    }
  printf("Converged in  %10ld iterations \n",itn);
  printf("Final residual norm = %10.3e\n\n", rnorm);
  printf("     Converged Solution\n");
  /* Output x*/
  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 (icol) NAG_FREE(icol);
  if (ipiv) NAG_FREE(ipiv);
  if (irow) NAG_FREE(irow);
  if (istr) NAG_FREE(istr);
  return exit_status;
}