/* nag_sparse_herm_chol_fac (f11jnc) Example Program.
 *
 * Copyright 2017 Numerical Algorithms Group.
 *
 * Mark 26.2, 2017.
 */

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

int main(void)
{
  /* Scalars */
  Integer exit_status = 0;
  double dscale, dtol;
  Integer i, la, lfill, n, nnz, nnzc, npivm;
  /* Arrays */
  Complex *a = 0;
  Integer *icol = 0, *ipiv = 0, *irow = 0, *istr = 0;
  char nag_enum_arg[100];
  /* NAG types */
  Nag_SparseSym_Piv pstrat;
  Nag_SparseSym_Fact mic;
  NagError fail;

  INIT_FAIL(fail);

  printf("nag_sparse_herm_chol_fac (f11jnc) Example Program Results\n");
  /* Skip heading in data file */
  scanf("%*[^\n]");
  /* Read algorithmic parameters */
  scanf("%" NAG_IFMT "%*[^\n]%" NAG_IFMT "%*[^\n]", &n, &nnz);

  /* Allocate memory */
  la = 3 * nnz;
  if (!(a = NAG_ALLOC(la, 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("%" NAG_IFMT "%lf%*[^\n]", &lfill, &dtol);
  scanf("%99s%*[^\n]", nag_enum_arg);
  /* 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("%lf%*[^\n]", &dscale);
  scanf("%99s%*[^\n]", nag_enum_arg);
  pstrat = (Nag_SparseSym_Piv) nag_enum_name_to_value(nag_enum_arg);

  /* Read the matrix a */
  for (i = 0; i < nnz; i++)
    scanf(" ( %lf , %lf ) %" NAG_IFMT "%" NAG_IFMT "%*[^\n] ",
          &a[i].re, &a[i].im, &irow[i], &icol[i]);

  /* Calculate incomplete Cholesky factorization 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;
  }

  /* Output original matrix */
  printf(" Original Matrix \n");
  printf("  n = %4" NAG_IFMT ", nnz  = %4" NAG_IFMT "\n", n, nnz);
  printf("%8s%16s%23s%9s\n", "i", "a[i]", "irow[i]", "icol[i]");
  for (i = 0; i < nnz; i++)
    printf("%8" NAG_IFMT " (%13.4e, %13.4e) %8" NAG_IFMT " %8" NAG_IFMT " \n",
           i, a[i].re, a[i].im, irow[i], icol[i]);
  printf("\n");

  /* Output details of the factorization */
  printf(" Factorization \n");
  printf("  n = %4" NAG_IFMT ", nnzc = %4" NAG_IFMT ", npivm = %4" NAG_IFMT
         "\n", n, nnzc, npivm);
  printf("%8s%16s%23s%9s\n", "i", "a[i]", "irow[i]", "icol[i]");
  for (i = nnz; i < nnz + nnzc; i++)
    printf("%8" NAG_IFMT " (%13.4e, %13.4e) %8" NAG_IFMT " %8" NAG_IFMT " \n",
           i, a[i].re, a[i].im, irow[i], icol[i]);
  printf("\n%8s%12s\n", "i", "ipiv[i-1]");
  for (i = 1; i <= n; i++)
    printf("%8" NAG_IFMT "%8" NAG_IFMT "\n", i, ipiv[i - 1]);

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