/* nag_sparse_complex_gen_precon_ilu (f11dnc) Example Program.
*
* Copyright 2021 Numerical Algorithms Group.
*
* Mark 27.3, 2021.
*/
#include <nag.h>
int main(void) {
/* Scalars */
Integer exit_status = 0;
double dtol;
Integer i, la, lfill, n, nnz, nnzc, npivm;
/* Arrays */
Complex *a = 0;
Integer *icol = 0, *idiag = 0, *ipivp = 0, *ipivq = 0, *irow = 0, *istr = 0;
char nag_enum_arg[40];
/* NAG types */
Nag_SparseNsym_Piv pstrat;
Nag_SparseNsym_Fact milu;
NagError fail;
INIT_FAIL(fail);
printf(
"nag_sparse_complex_gen_precon_ilu (f11dnc) Example Program Results \n\n");
/* Skip heading in data file */
scanf("%*[^\n] ");
/* Read algorithmic parameters */
scanf("%" NAG_IFMT "%*[^\n]", &n);
scanf("%" NAG_IFMT "%*[^\n]", &nnz);
scanf("%" NAG_IFMT "%lf%*[^\n]", &lfill, &dtol);
scanf("%39s%*[^\n]", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
pstrat = (Nag_SparseNsym_Piv)nag_enum_name_to_value(nag_enum_arg);
scanf("%39s%*[^\n]", nag_enum_arg);
milu = (Nag_SparseNsym_Fact)nag_enum_name_to_value(nag_enum_arg);
la = 2 * nnz;
if (!(a = NAG_ALLOC((la), Complex)) || !(icol = NAG_ALLOC((la), Integer)) ||
!(idiag = NAG_ALLOC((n), Integer)) ||
!(ipivp = NAG_ALLOC((n), Integer)) ||
!(ipivq = 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 the matrix a */
for (i = 0; i < nnz; ++i)
scanf(" ( %lf , %lf ) %" NAG_IFMT "%" NAG_IFMT "%*[^\n]", &a[i].re,
&a[i].im, &irow[i], &icol[i]);
/* Calculate incomplete LU factorization */
/* nag_sparse_complex_gen_precon_ilu (f11dnc)
* Complex sparse non-Hermitian linear systems, incomplete LU factorization
*/
nag_sparse_complex_gen_precon_ilu(n, nnz, a, la, irow, icol, lfill, dtol,
pstrat, milu, ipivp, ipivq, istr, idiag,
&nnzc, &npivm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sparse_real_gen_precon_ilu (f11dac).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
/* Output original matrix */
printf(" Original Matrix\n n = %6" NAG_IFMT "\n", n);
printf(" nnz = %6" NAG_IFMT "\n", nnz);
for (i = 0; i < nnz; ++i)
printf("%8" NAG_IFMT " (%16.4e, %16.4e) %8" NAG_IFMT "%8" NAG_IFMT "\n", i,
a[i].re, a[i].im, irow[i], icol[i]);
printf("\n");
/* Output details of the factorization */
printf(" Factorization\n n = %6" NAG_IFMT "\n", n);
printf(" nnz = %6" NAG_IFMT "\n", nnzc);
printf(" npivm = %6" NAG_IFMT "\n", npivm);
for (i = nnz; i < nnz + nnzc; ++i)
printf("%8" NAG_IFMT " (%16.4e, %16.4e) %8" NAG_IFMT "%8" NAG_IFMT "\n", i,
a[i].re, a[i].im, irow[i], icol[i]);
printf("\n i ipivp[i] ipivq[i]\n"); /* */
for (i = 0; i < n; ++i)
printf("%10" NAG_IFMT "%10" NAG_IFMT "%10" NAG_IFMT "\n", i, ipivp[i],
ipivq[i]);
END:
NAG_FREE(a);
NAG_FREE(icol);
NAG_FREE(idiag);
NAG_FREE(ipivp);
NAG_FREE(ipivq);
NAG_FREE(irow);
NAG_FREE(istr);
return exit_status;
}