/* nag_superlu_refine_lu (f11mhc) Example Program.
 *
 * Copyright 2005 Numerical Algorithms Group.
 *
 * Mark 8, 2005.
 */

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

/* Table of constant values */

static Integer c__1 = 1;
static Integer c__80 = 80;
static Integer c__0 = 0;

int main(void)
{
  double flop, thresh;
  Integer exit_status=0, i, j;
  Integer n, nnz, nnzl, nnzu, nrhs, nzlmx, nzlumx, nzumx;
  double *a=0, *b=0, *berr=0, *ferr=0, *lval=0, *uval=0, *x=0;
  Integer *icolzp=0, *il=0, *iprm=0, *irowix=0, *iu=0;
  /* Nag types */
  NagError fail;
  Nag_OrderType order = Nag_ColMajor;
  Nag_MatrixType matrix = Nag_GeneralMatrix;
  Nag_DiagType diag = Nag_NonUnitDiag;
  Nag_ColumnPermutationType ispec;
  Nag_TransType trans;


  INIT_FAIL(fail);
  Vprintf( "nag_superlu_refine_lu (f11mhc) Example Program Results\n\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");
  /* Read order of matrix and number of right hand sides */
  Vscanf("%ld%ld%*[^\n] ",   &n,  &nrhs);
  /* Read the matrix A */
  if ( !(icolzp = NAG_ALLOC(n+1, Integer)))
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  for (i = 1; i <= n + 1; ++i)
    Vscanf("%ld%*[^\n] ", &icolzp[i - 1]);
  nnz = icolzp[n] - 1;
  /* Allocate memory */
  if ( !(irowix = NAG_ALLOC(nnz, Integer)) ||
       !(a = NAG_ALLOC(nnz, double)) ||
       !(il = NAG_ALLOC(7*n+8*nnz+4, Integer)) ||
       !(iu = NAG_ALLOC(2*n+8*nnz+1, Integer)) ||
       !(uval = NAG_ALLOC(8*nnz, double)) ||
       !(lval = NAG_ALLOC(8*nnz, double)) ||
       !(b = NAG_ALLOC(n * nrhs, double)) ||
       !(x = NAG_ALLOC(n * nrhs, double)) ||
       !(berr = NAG_ALLOC(nrhs, double)) ||
       !(ferr = NAG_ALLOC(nrhs, double)) ||
       !(iprm = NAG_ALLOC(7*n, Integer)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  for (i = 1; i <= nnz; ++i)
    Vscanf("%lf%ld%*[^\n] ",   &a[i - 1],  &irowix[i - 1]);
  /* Read the right hand sides */
  for (j = 1; j <= nrhs; ++j)
    {
      for (i = 1; i <= n; ++i) {
        Vscanf("%lf", &x[j*n + i - n - 1]);
        b[j*n + i - n - 1] =  x[j*n + i - n - 1];
      }
      Vscanf("%*[^\n] ");
    }
  /* Calculate COLAMD permutation */
  ispec = Nag_Sparse_Colamd;
  /* nag_superlu_column_permutation (f11mdc).
   * Real sparse nonsymmetric linear systems, setup for
   * nag_superlu_lu_factorize (f11mec)
   */
  nag_superlu_column_permutation(ispec, n, icolzp, irowix, iprm, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_superlu_column_permutation (f11mdc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* Factorise */
  thresh = 1.;
  nzlmx = 8*nnz;
  nzlumx = 8*nnz;
  nzumx = 8*nnz;
  /* nag_superlu_lu_factorize (f11mec).
   * LU factorization of real sparse matrix
   */
  nag_superlu_lu_factorize(n, irowix, a, iprm, thresh, nzlmx, &nzlumx, nzumx,
                           il, lval, iu, uval, &nnzl, &nnzu, &flop, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_superlu_lu_factorize (f11mec).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* Compute solution in array X */
  trans = Nag_NoTrans;
  /* nag_superlu_solve_lu (f11mfc).
   * Solution of real sparse simultaneous linear equations
   * (coefficient matrix already factorized)
   */
  nag_superlu_solve_lu(order, trans , n, iprm, il, lval, iu, uval, nrhs, x,
                       n, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_superlu_solve_lu (f11mfc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Improve solution, and compute backward errors and estimated */
  /* bounds on the forward errors */
  /* nag_superlu_refine_lu (f11mhc).
   * Refined solution with error bounds of real system of
   * linear equations, multiple right-hand sides
   */
  nag_superlu_refine_lu(order, trans, n, icolzp, irowix, a, iprm, il, lval,
                        iu, uval, nrhs, b, n, x, n, ferr, berr,
                        &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_superlu_refine_lu (f11mhc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print solution */
  Vprintf("\n");
  /* nag_gen_real_mat_print (x04cac).
   * Print real general matrix (easy-to-use)
   */
  nag_gen_real_mat_print(order, matrix, diag, n, nrhs,
                         x, n, "Solutions", NULL, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_gen_real_mat_print (x04cac).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* nag_gen_real_mat_print_comp (x04cbc).
   * Print real general matrix (comprehensive)
   */
  nag_gen_real_mat_print_comp(order, matrix, diag, nrhs, c__1, ferr, nrhs,
                              "%8.2g", "Estimated Forward Error", Nag_NoLabels,
                              NULL, Nag_NoLabels, NULL, c__80, c__0, NULL,
                              &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_gen_real_mat_print_comp (x04cbc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* nag_gen_real_mat_print_comp (x04cbc), see above. */
  nag_gen_real_mat_print_comp(order, matrix, diag, nrhs, c__1, berr, nrhs,
                              "%8.2g", "Backward Error", Nag_NoLabels, NULL,
                              Nag_NoLabels, NULL, c__80, c__0, NULL, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_gen_real_mat_print_comp (x04cbc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

 END:
  if (a) NAG_FREE(a);
  if (b) NAG_FREE(b);
  if (berr) NAG_FREE(berr);
  if (ferr) NAG_FREE(ferr);
  if (lval) NAG_FREE(lval);
  if (uval) NAG_FREE(uval);
  if (x) NAG_FREE(x);
  if (icolzp) NAG_FREE(icolzp);
  if (il) NAG_FREE(il);
  if (iprm) NAG_FREE(iprm);
  if (irowix) NAG_FREE(irowix);
  if (iu) NAG_FREE(iu);
  return exit_status;
}