/* nag_sparse_real_symm_precon_ichol (f11jac) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.3, 2024.
 *
 */

#include <nag.h>
#include <stdio.h>

int main(void) {
  double dtol;
  double *a;
  double dscale;
  Integer *irow, *icol;
  Integer *ipiv, nnzc, *istr;
  Integer exit_status = 0, i, n, lfill, npivm;
  Integer nnz;
  Integer num;
  char nag_enum_arg[40];
  Nag_SparseSym_Piv pstrat;
  Nag_SparseSym_Fact mic;
  Nag_Sparse_Comm comm;
  NagError fail;

  INIT_FAIL(fail);

  printf(
      "nag_sparse_real_symm_precon_ichol (f11jac) Example Program Results\n\n");

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

  /* Read algorithmic parameters */
  scanf("%" NAG_IFMT "", &n);
  scanf("%*[^\n]");
  scanf("%" NAG_IFMT "%*[^\n]", &nnz);
  scanf("%" NAG_IFMT "%lf%*[^\n]", &lfill, &dtol);
  scanf("%39s%lf%*[^\n]", nag_enum_arg, &dscale);
  /* nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  mic = (Nag_SparseSym_Fact)nag_enum_name_to_value(nag_enum_arg);
  scanf("%39s%*[^\n]", nag_enum_arg);
  pstrat = (Nag_SparseSym_Piv)nag_enum_name_to_value(nag_enum_arg);

  /* Allocate memory */
  num = 2 * nnz;
  ipiv = NAG_ALLOC(n, Integer);
  istr = NAG_ALLOC(n + 1, Integer);
  irow = NAG_ALLOC(num, Integer);
  icol = NAG_ALLOC(num, Integer);
  a = NAG_ALLOC(num, double);

  if (!ipiv || !istr || !irow || !icol || !a) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Read the matrix a */

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

  /* Calculate incomplete Cholesky factorization */

  /* nag_sparse_real_symm_precon_ichol (f11jac).
   * Incomplete Cholesky factorization (symmetric)
   */
  nag_sparse_real_symm_precon_ichol(n, nnz, &a, &num, &irow, &icol, lfill, dtol,
                                    mic, dscale, pstrat, ipiv, istr, &nnzc,
                                    &npivm, &comm, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_sparse_real_symm_precon_ichol (f11jac).\n%s\n",
           fail.message);
    exit_status = 1;
    goto END;
  }

  /* Output original matrix */

  printf(" Original Matrix \n");
  printf(" n     = %6" NAG_IFMT "\n", n);
  printf(" nnz   = %6" NAG_IFMT "\n\n", nnz);
  for (i = 1; i <= nnz; ++i)
    printf(" %8" NAG_IFMT "%16.4e%8" NAG_IFMT "%8" NAG_IFMT "\n", i, a[i - 1],
           irow[i - 1], icol[i - 1]);
  printf("\n");

  /* Output details of the factorization */
  printf(" Factorization\n n = %6" NAG_IFMT " \n nnz = %6" NAG_IFMT "\n", n,
         nnzc);
  printf(" npivm = %6" NAG_IFMT "\n\n", npivm);
  for (i = nnz + 1; i <= nnz + nnzc; ++i)
    printf(" %8" NAG_IFMT "%16.4e%8" NAG_IFMT "%8" NAG_IFMT "\n", i, a[i - 1],
           irow[i - 1], icol[i - 1]);

  printf("\n        i     ipiv(i) \n");
  for (i = 1; i <= n; ++i)
    printf(" %8" NAG_IFMT "%8" NAG_IFMT "\n", i, ipiv[i - 1]);

END:
  NAG_FREE(irow);
  NAG_FREE(icol);
  NAG_FREE(a);
  NAG_FREE(istr);
  NAG_FREE(ipiv);
  return exit_status;
}