/* nag_sparse_nsym_fac_solve (f11dcc) 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                dtol;
  double                *a = 0, *b = 0;
  double                *x = 0;
  double                rnorm;
  double                tol;
  Integer               exit_status = 0;
  Integer               *irow, *icol;
  Integer               *istr = 0, *idiag, *ipivp = 0, *ipivq = 0;
  Integer               i, m, n, nnzc;
  Integer               lfill, npivm;
  Integer               maxitn;
  Integer               itn;
  Integer               nnz;
  Integer               num;
  char                  nag_enum_arg[40];
  Nag_SparseNsym_Method method;
  Nag_SparseNsym_Piv    pstrat;
  Nag_SparseNsym_Fact   milu;
  Nag_Sparse_Comm       comm;
  NagError              fail;

  INIT_FAIL(fail);

  printf("nag_sparse_nsym_fac_sol (f11dcc) Example Program Results\n");

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

  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_SparseNsym_Method) nag_enum_name_to_value(nag_enum_arg);

  scanf("%ld%lf%*[^\n]", &lfill, &dtol);
  scanf("%s%*[^\n]", nag_enum_arg);
  pstrat = (Nag_SparseNsym_Piv) nag_enum_name_to_value(nag_enum_arg);
  scanf("%s%*[^\n]", nag_enum_arg);
  milu = (Nag_SparseNsym_Fact) nag_enum_name_to_value(nag_enum_arg);

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

  /* Read the matrix a */

  num = 2*nnz;
  istr = NAG_ALLOC(n+1, Integer);
  idiag = NAG_ALLOC(n, Integer);
  ipivp = NAG_ALLOC(n, Integer);
  ipivq = NAG_ALLOC(n, Integer);
  x = NAG_ALLOC(n, double);
  b = NAG_ALLOC(n, double);
  a = NAG_ALLOC(num, double);
  irow = NAG_ALLOC(num, Integer);
  icol = NAG_ALLOC(num, Integer);
  if (!istr || !idiag || !ipivp || !ipivq || !irow || !icol || !a || !x || !b)
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }


  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]");

  /* Calculate incomplete LU factorization */

  /* nag_sparse_nsym_fac (f11dac).
   * Incomplete LU factorization (nonsymmetric)
   */
  nag_sparse_nsym_fac(n, nnz, &a, &num, &irow, &icol, lfill, dtol, pstrat,
                      milu, ipivp, ipivq, istr, idiag, &nnzc, &npivm, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_sparse_nsym_fac (f11dac).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* nag_sparse_nsym_fac_sol (f11dcc).
   * Solver with incomplete LU preconditioning (nonsymmetric)
   */
  /* Solve Ax = b using nag_sparse_nsym_fac_sol (f11dcc) */
  nag_sparse_nsym_fac_sol(method, n, nnz, a, num, irow, icol, ipivp, ipivq,
                          istr, idiag, b, m, tol, maxitn, x, &rnorm, &itn,
                          &comm, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_sparse_nsym_fac_sol (f11dcc).\n%s\n",
	    fail.message);
    exit_status = 1;
    goto END;
  }

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

  /* Output x */

  printf("           x\n");
  for (i = 1; i <= n; ++i)
    printf(" %16.6e\n", x[i-1]);

 END:
  if (istr) NAG_FREE(istr);
  if (idiag) NAG_FREE(idiag);
  if (ipivp) NAG_FREE(ipivp);
  if (ipivq) NAG_FREE(ipivq);
  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;
}