/* nag_sparse_sym_chol_fac (f11jac) 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             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);

  /* 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_sym_chol_fac (f11jac) Example Program Results\n\n");

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

  /* Read algorithmic parameters */
  fscanf(fpin, "%ld", &n);
  fscanf(fpin, "%*[^\n]");
  fscanf(fpin, "%ld%*[^\n]", &nnz);
  fscanf(fpin, "%ld%lf%*[^\n]", &lfill, &dtol);
  fscanf(fpin, "%s%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);
  fscanf(fpin, "%s%*[^\n]", nag_enum_arg);
  pstrat = (Nag_SparseNsym_Piv) nag_enum_name_to_value(nag_enum_arg);

  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)
    {
      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]);

  /* Calculate incomplete Cholesky factorization */

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

  /* Output original matrix */

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

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

  fprintf(fpout, "\n        i     ipiv(i) \n");
  for (i = 1; i <= n; ++i)
    fprintf(fpout, " %8ld%8ld\n", i, ipiv[i-1]);

 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  NAG_FREE(irow);
  NAG_FREE(icol);
  NAG_FREE(a);
  NAG_FREE(istr);
  NAG_FREE(ipiv);
  return exit_status;
}