```/* nag_sparse_direct_real_gen_lu (f11mec) Example Program.
*
* Copyright 2020 Numerical Algorithms Group.
*
* Mark 27.1, 2020.
*/

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

/* Table of constant values */

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

INIT_FAIL(fail);

/* nag_sparse_direct_real_gen_lu (f11mec).
* LU factorization of real sparse matrix
*/
printf("nag_sparse_direct_real_gen_lu (f11mec) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n] ");
/* Read order of matrix */
scanf("%" NAG_IFMT "%*[^\n] ", &n);
/* Read the matrix A */
/* Allocate memory */
if (!(icolzp = NAG_ALLOC(n + 1, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 1; i <= n + 1; ++i)
scanf("%" NAG_IFMT "%*[^\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)) ||
!(iprm = NAG_ALLOC(7 * n, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 1; i <= nnz; ++i)
scanf("%lf%" NAG_IFMT "%*[^\n] ", &a[i - 1], &irowix[i - 1]);
/* Calculate COLAMD permutation */
ispec = Nag_Sparse_Colamd;
/* nag_sparse_direct_real_gen_setup (f11mdc).
* Real sparse nonsymmetric linear systems, setup for
* nag_sparse_direct_real_gen_lu (f11mec)
*/
nag_sparse_direct_real_gen_setup(ispec, n, icolzp, irowix, iprm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sparse_direct_real_gen_setup (f11mdc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
/* Factorise */
thresh = 1.;
nzlmx = 8 * nnz;
nzlumx = 8 * nnz;
nzumx = 8 * nnz;
/* nag_sparse_direct_real_gen_lu (f11mec), see above. */
nag_sparse_direct_real_gen_lu(n, irowix, a, iprm, thresh, nzlmx, &nzlumx,
nzumx, il, lval, iu, uval, &nnzl, &nnzu, &flop,
&fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sparse_direct_real_gen_lu (f11mec).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Output results */
printf("\n");
printf("Number of nonzeros in factors (excluding unit diagonal)\n");
printf("%8" NAG_IFMT "\n\n", nnzl + nnzu - n);
/* nag_file_print_matrix_real_gen_comp (x04cbc).
* Print real general matrix (comprehensive)
*/
fflush(stdout);
nag_file_print_matrix_real_gen_comp(
order, matrix, diag, 1, 10, lval, 1, "%6.2f", "Factor elements in LVAL",
Nag_NoLabels, NULL, Nag_NoLabels, NULL, 80, 1, 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_gen_comp (x04cbc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

printf("\n");
/* nag_file_print_matrix_real_gen_comp (x04cbc), see above. */
fflush(stdout);
nag_file_print_matrix_real_gen_comp(
order, matrix, diag, 1, 4, uval, 1, "%6.2f", "Factor elements in LVAL",
Nag_NoLabels, NULL, Nag_NoLabels, NULL, 80, 1, 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_gen_comp (x04cbc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

END:
NAG_FREE(a);
NAG_FREE(lval);
NAG_FREE(uval);
NAG_FREE(icolzp);
NAG_FREE(il);
NAG_FREE(iprm);
NAG_FREE(irowix);
NAG_FREE(iu);

return exit_status;
}
```