/* nag_sparse_herm_precon_ssor_solve (f11jrc) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.1, 2017.
*/
#include <nag.h>
#include <nag_stdlib.h>
#include <naga02.h>
#include <nagf11.h>
int main(void)
{
/* Scalars */
Integer exit_status = 0;
double omega;
Integer i, n, nnz;
/* Arrays */
char nag_enum_arg[100];
Complex *a = 0, *x = 0, *y = 0;
double *rdiag = 0;
Integer *icol = 0, *irow = 0;
/* NAG types */
Nag_SparseSym_CheckData check;
NagError fail;
INIT_FAIL(fail);
printf("nag_sparse_herm_precon_ssor_solve (f11jrc) Example Program Results");
printf("\n");
/* Skip heading in data file */
scanf("%*[^\n]");
/* Read algorithmic parameters */
scanf("%" NAG_IFMT "%*[^\n] ", &n);
scanf("%" NAG_IFMT "%*[^\n] ", &nnz);
/* Allocate memory */
if (!(a = NAG_ALLOC(nnz, Complex)) ||
!(x = NAG_ALLOC(n, Complex)) ||
!(y = NAG_ALLOC(n, Complex)) ||
!(rdiag = NAG_ALLOC(n, double)) ||
!(icol = NAG_ALLOC(nnz, Integer)) || !(irow = NAG_ALLOC(nnz, Integer))
)
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
scanf("%99s%*[^\n] ", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
check = (Nag_SparseSym_CheckData) nag_enum_name_to_value(nag_enum_arg);
scanf("%lf%*[^\n]", &omega);
/* 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]);
/* Read rhs vector y */
for (i = 0; i < n; i++)
scanf(" ( %lf , %lf ) ", &y[i].re, &y[i].im);
scanf("%*[^\n]");
/* Fill in the diagonal part */
for (i = 0; i < nnz; i++)
if (irow[i] == icol[i])
rdiag[irow[i] - 1] = 1.0 / (double) (a[i].re);
/* nag_sparse_herm_precon_ssor_solve (f11jrc).
* Solution of linear system involving preconditioning matrix
* generated by applying SSOR to complex sparse Hermitian matrix
*/
nag_sparse_herm_precon_ssor_solve(n, nnz, a, irow, icol, rdiag,
omega, check, y, x, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sparse_herm_precon_ssor_solve (f11jrc)\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
/* Output x */
printf(" Converged Solution\n");
for (i = 0; i < n; i++)
printf(" (%13.4e, %13.4e) \n", x[i].re, x[i].im);
END:
NAG_FREE(a);
NAG_FREE(x);
NAG_FREE(y);
NAG_FREE(rdiag);
NAG_FREE(icol);
NAG_FREE(irow);
return exit_status;
}