/* nag_sparse_herm_basic_setup (f11grc) Example Program.
 *
 * Copyright 2011, Numerical Algorithms Group.
 *
 * Mark 23, 2011.
 */

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

int main(void)
{
  /* Scalars */
  Integer                   exit_status = 0;
  double                    anorm, dscale, dtol, sigerr, sigmax, sigtol,
                            stplhs, stprhs, tol;
  Integer                   i, irevcm, iterm, itn, its, la, lfill, lwork,
                            lwreq, maxitn, maxits, monit, n, nnz, nnzc, npivm;
  /* Arrays */
  char                      nag_enum_arg[100];
  Complex                   *a = 0, *b = 0, *work = 0, *x = 0;
  double                    *wgt = 0;
  Integer                   *icol = 0, *ipiv = 0, *irow = 0, *istr = 0;
  /* NAG types */
  Nag_SparseSym_Method      method;
  Nag_SparseSym_PrecType    precon;
  Nag_SparseSym_Bisection   sigcmp;
  Nag_NormType              norm;
  Nag_SparseSym_Weight      weight;
  Nag_SparseSym_Fact        mic;
  Nag_SparseSym_Piv         pstrat;
  NagError                  fail, fail1;

  INIT_FAIL(fail);
  INIT_FAIL(fail1);

  printf("nag_sparse_herm_basic_setup (f11grc) Example Program Results\n");
  /* Skip heading in data file*/
  scanf("%*[^\n]");
  scanf("%ld%*[^\n]", &n);
  scanf("%ld%*[^\n]", &nnz);
  la = 2 * nnz;
  lwork = 200;
  if (
      !(a = NAG_ALLOC(la, Complex)) ||
      !(b = NAG_ALLOC(n, Complex)) ||
      !(work = NAG_ALLOC(lwork, Complex)) ||
      !(x = NAG_ALLOC(n, Complex)) ||
      !(wgt = NAG_ALLOC(n, double)) ||
      !(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;
  }
  /* Read or initialize the parameters for the iterative solver*/
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  scanf("%s%*[^\n] ", nag_enum_arg);
  method = (Nag_SparseSym_Method) nag_enum_name_to_value(nag_enum_arg);
  scanf("%s%*[^\n] ", nag_enum_arg);
  precon = (Nag_SparseSym_PrecType) nag_enum_name_to_value(nag_enum_arg);
  scanf("%s%*[^\n] ", nag_enum_arg);
  sigcmp = (Nag_SparseSym_Bisection) nag_enum_name_to_value(nag_enum_arg);
  scanf("%s%*[^\n] ", nag_enum_arg);
  norm = (Nag_NormType) nag_enum_name_to_value(nag_enum_arg);
  scanf("%s%*[^\n] ", nag_enum_arg);
  weight = (Nag_SparseSym_Weight) nag_enum_name_to_value(nag_enum_arg);

  scanf("%ld%*[^\n] ", &iterm);
  scanf("%lf%ld%*[^\n] ", &tol, &maxitn);
  scanf("%ld%*[^\n] ", &monit);
  
  /* Read the parameters for the preconditioner*/
  scanf("%ld%lf%*[^\n] ", &lfill, &dtol);
  scanf("%s%*[^\n] ", nag_enum_arg);
  mic = (Nag_SparseSym_Fact) nag_enum_name_to_value(nag_enum_arg);
  scanf("%lf%*[^\n]", &dscale);
  scanf("%s%*[^\n] ", nag_enum_arg);
  pstrat = (Nag_SparseSym_Piv) nag_enum_name_to_value(nag_enum_arg);

  /* Read the non-zero elements of the matrix A*/
  for (i = 0; i < nnz; i++)
    scanf(" ( %lf , %lf ) %ld%ld%*[^\n]",
	  &a[i].re, &a[i].im, &irow[i], &icol[i]);
  
  /* Read right-hand side vector b and initial approximate solution x*/
  for (i = 0; i < n; i++) scanf(" ( %lf , %lf ) ", &b[i].re, &b[i].im);
  scanf("%*[^\n]");
  for (i = 0; i < n; i++) scanf(" ( %lf , %lf ) ", &x[i].re, &x[i].im);
  
  /* Calculate incomplete Cholesky factorization preconditioner using 
   * nag_sparse_herm_chol_fac (f11jnc).
   * Complex sparse Hermitian matrix, incomplete Cholesky factorization
   */
  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;
    }
  
  /* Initialize the solver using nag_sparse_herm_basic_setup (f11grc). */
  anorm = 0.0;
  sigmax = 0.0;
  sigtol = 0.01;
  maxits = n;
  nag_sparse_herm_basic_setup(method, precon, sigcmp, norm, weight, iterm,
			      n, tol, maxitn, anorm, sigmax, sigtol, maxits,
			      monit, &lwreq, work, lwork, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_sparse_herm_basic_setup (f11grc)\n%s\n",
	     fail.message);
      exit_status = 2;
      goto END;
    }

  /* Call solver repeatedly to solve the equations
   * Note that the arrays b and x are overwritten on final exit:
   * x will contain the solution and b the residual vector
   */
  irevcm = 0;
  lwreq = lwork;
  /* First call to nag_sparse_herm_basic_solver (f11gsc).
   * Complex sparse Hermitian linear systems, preconditioned conjugate
   * gradient or Lanczos
   */
  nag_sparse_herm_basic_solver(&irevcm, x, b, wgt, work, lwreq, &fail);
  while (irevcm != 4) {
    switch (irevcm) {
    case 1:
      /* nag_sparse_herm_matvec (f11xsc).
       * Complex sparse Hermitian matrix vector multiply
       */
      nag_sparse_herm_matvec(n, nnz, a, irow, icol, Nag_SparseSym_NoCheck,
			     x, b, &fail1);
      break;
    case 2:
      /* nag_sparse_herm_precon_ichol_solve (f11jpc).
       * Solution of complex linear system involving incomplete Cholesky
       * preconditioning matrix generated by f11jnc
       */
      nag_sparse_herm_precon_ichol_solve(n, a, la, irow, icol, ipiv, istr,
                                         Nag_SparseSym_NoCheck, x, b, &fail1);
      break;
    case 3:
      /* nag_sparse_herm_basic_diagnostic (f11gtc).
       * Complex sparse Hermitian linear systems, diagnostic for f11gsc
       */
      nag_sparse_herm_basic_diagnostic(&itn, &stplhs, &stprhs, &anorm, &sigmax,
                                       &its, &sigerr, work, lwreq, &fail1);
      printf("\nMonitoring at iteration no.%4ld\n", itn);
      printf("residual norm:%14.4e\n", stplhs);
      printf("%6sSolution vector%18sResidual vector\n", "", "");
      for (i = 0; i < n; i++)
	printf(" (%11.4e, %11.4e)    (%11.4e, %11.4e)\n",
	       x[i].re, x[i].im, b[i].re, b[i].im);
      printf("\n");
    }
    if (fail1.code != NE_NOERROR) irevcm = 6;
    /* Next call to nag_sparse_herm_basic_solver (f11gsc). */
    nag_sparse_herm_basic_solver(&irevcm, x, b, wgt, work, lwreq, &fail);
  }
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_sparse_herm_basic_solver (f11gsc).\n%s\n",
	   fail.message);
    exit_status = 3;
    goto END;
  }

  /* Obtain information about the computation using
     nag_sparse_herm_basic_diagnostic (f11gtc)
   */
  nag_sparse_herm_basic_diagnostic(&itn, &stplhs, &stprhs, &anorm, &sigmax, 
                                   &its, &sigerr, work, lwreq, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_sparse_herm_basic_diagnostic (f11gtc)\n%s\n",
	     fail.message);
      exit_status = 4;
      goto END;
    }

  /* Print the output data*/
  printf("Final Results\n");
  printf("Number of iterations for convergence:     %5ld \n", itn);
  printf("Residual norm:                            %14.4e\n", stplhs);
  printf("Right-hand side of termination criterion: %14.4e \n", stprhs);
  printf("1-norm of matrix A:                       %14.4e \n", anorm);
  printf("Largest singular value of A_bar:          %14.4e \n", sigmax);
  /* Output x*/
  printf("\n%6sSolution vector%18sResidual vector\n", "", "");
  for (i = 0; i < n; i++)
    printf(" (%11.4e, %11.4e)   (%11.4e, %11.4e)\n",
	   x[i].re, x[i].im, b[i].re, b[i].im);
  printf("\n");
 END:
  if (a) NAG_FREE(a);
  if (b) NAG_FREE(b);
  if (work) NAG_FREE(work);
  if (x) NAG_FREE(x);
  if (wgt) NAG_FREE(wgt);
  if (icol) NAG_FREE(icol);
  if (ipiv) NAG_FREE(ipiv);
  if (irow) NAG_FREE(irow);
  if (istr) NAG_FREE(istr);
  return exit_status;
}