/* nag_sparse_nsym_sol (f11dec) Example Program.
 *
 * Copyright 1998 Numerical Algorithms Group.
 *
 * Mark 5, 1998.
 */

#include <nag.h>
#include <nagx04.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nag_string.h>
#include <nagf11.h>

int main(int argc, char *argv[])
{
  FILE                    *fpin, *fpout;
  double                  *a = 0, *b = 0, *x = 0;
  double                  omega;
  double                  rnorm;
  double                  tol;
  Integer                 exit_status = 0;
  Integer                 *icol = 0, *irow = 0;
  Integer                 i, m, n;
  Integer                 maxitn, itn;
  Integer                 nnz;
  char                    nag_enum_arg[40];
  Nag_SparseNsym_Method   method;
  Nag_SparseNsym_PrecType precon;
  Nag_Sparse_Comm         comm;
  NagError                fail;

  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);

  fprintf(fpout, "nag_sparse_nsym_sol (f11dec) Example Program Results\n");
  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n]");
  fscanf(fpin, "%ld%*[^\n]", &n);
  fscanf(fpin, "%ld%*[^\n]", &nnz);

  fscanf(fpin, "%s", 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);
  fscanf(fpin, "%s%*[^\n]", nag_enum_arg);
  precon = (Nag_SparseNsym_PrecType) nag_enum_name_to_value(nag_enum_arg);

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

  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)
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = 1;
      goto END;
    }

  /* Read the matrix a */

  for (i = 1; i <= nnz; ++i)
    fscanf(fpin, "%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)
    fscanf(fpin, "%lf", &b[i-1]);
  fscanf(fpin, "%*[^\n]");

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

  /* Solve Ax = b using nag_sparse_nsym_sol (f11dec) */

  /* nag_sparse_nsym_sol (f11dec).
   * Solver with no Jacobi/SSOR preconditioning (nonsymmetric)
   */
  nag_sparse_nsym_sol(method, precon, n, nnz, a, irow, icol, omega, b, m, tol,
                      maxitn, x, &rnorm, &itn, &comm, &fail);

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

  /* Output x */
  fprintf(fpout, "           x\n");
  for (i = 1; i <= n; ++i)
    fprintf(fpout, " %16.6e\n", x[i-1]);

 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  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;
}