/* 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 *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;

  Nag_SparseNsym_Method method;
  Nag_SparseNsym_Piv pstrat;
  Nag_SparseNsym_Fact milu;
  Nag_Sparse_Comm comm;

  char char_enum[20];

  Vprintf("f11dcc Example Program Results\n");

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

  Vscanf("%ld%*[^\n]",&n);
  Vscanf("%ld%*[^\n]",&nnz);
  Vscanf("%s%*[^\n]",char_enum);
  if (!strcmp(char_enum, "RGMRES"))
    method = Nag_SparseNsym_RGMRES;
  else if (!strcmp(char_enum, "CGS"))
    method = Nag_SparseNsym_CGS;
  else if (!strcmp(char_enum, "BiCGSTAB"))
    method = Nag_SparseNsym_BiCGSTAB;
  else
    {
      Vprintf("Unrecognised string for method enum representation.\n");
      return EXIT_FAILURE;
    }

  Vscanf("%ld%lf%*[^\n]",&lfill,&dtol);
  Vscanf("%s%*[^\n]", char_enum);
  if (!strcmp(char_enum, "NoPiv"))
    pstrat = Nag_SparseNsym_NoPiv;
  else if (!strcmp(char_enum, "UserPiv"))
    pstrat = Nag_SparseNsym_UserPiv;
  else if (!strcmp(char_enum, "PartialPiv"))
    pstrat = Nag_SparseNsym_PartialPiv;
  else if (!strcmp(char_enum, "CompletePiv"))
    pstrat = Nag_SparseNsym_CompletePiv;
  else
    {
      Vprintf("Unrecognised string for psstrat enum representation.\n");
      return EXIT_FAILURE;
    }

  Vscanf("%s%*[^\n]", char_enum);
  if (!strcmp(char_enum, "ModFact"))
    milu = Nag_SparseNsym_ModFact;
  else if (!strcmp(char_enum, "UnModFact"))
    milu = Nag_SparseNsym_UnModFact;
  else
    {
      Vprintf("Unrecognised string for milu enum representation.\n");
      return EXIT_FAILURE;
    }
  Vscanf("%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)
    {
      Vprintf("Allocation failure\n");
      return EXIT_FAILURE;
    }


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

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

  /* Calculate incomplete LU factorization */

  f11dac(n, nnz, &a, &num, &irow, &icol, lfill, dtol, pstrat, milu,
         ipivp, ipivq, istr, idiag, &nnzc, &npivm, NAGERR_DEFAULT);

  /* Solve Ax = b using F11DCC */

  f11dcc(method, n, nnz, a, num, irow, icol, ipivp, ipivq, istr,
         idiag, b, m, tol, maxitn, x, &rnorm, &itn, &comm, NAGERR_DEFAULT);

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

  /* Output x */

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

  NAG_FREE(istr);
  NAG_FREE(idiag);
  NAG_FREE(ipivp);
  NAG_FREE(ipivq);
  NAG_FREE(irow);
  NAG_FREE(icol);
  NAG_FREE(a);
  NAG_FREE(x);
  NAG_FREE(b);

  return EXIT_SUCCESS;
}