NAG Library Manual, Mark 28.6
```/* nag_lapacklin_zsyrfs (f07nvc) Example Program.
*
* Copyright 2022 Numerical Algorithms Group.
*
* Mark 28.6, 2022.
*/

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

int main(void) {
/* Scalars */
Integer i, j, n, nrhs, pda, pdaf, pdb, pdx;
Integer ferr_len, berr_len;
Integer exit_status = 0;
Nag_UploType uplo;
NagError fail;
Nag_OrderType order;
/* Arrays */
Integer *ipiv = 0;
char nag_enum_arg[40];
Complex *a = 0, *af = 0, *b = 0, *x = 0;
double *berr = 0, *ferr = 0;

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
#define AF(I, J) af[(J - 1) * pdaf + I - 1]
#define B(I, J) b[(J - 1) * pdb + I - 1]
#define X(I, J) x[(J - 1) * pdx + I - 1]
order = Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 1]
#define AF(I, J) af[(I - 1) * pdaf + J - 1]
#define B(I, J) b[(I - 1) * pdb + J - 1]
#define X(I, J) x[(I - 1) * pdx + J - 1]
order = Nag_RowMajor;
#endif

INIT_FAIL(fail);

printf("nag_lapacklin_zsyrfs (f07nvc) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &n, &nrhs);
#ifdef NAG_COLUMN_MAJOR
pda = n;
pdaf = n;
pdb = n;
pdx = n;
#else
pda = n;
pdaf = n;
pdb = nrhs;
pdx = nrhs;
#endif

ferr_len = nrhs;
berr_len = nrhs;

/* Allocate memory */
if (!(ipiv = NAG_ALLOC(n, Integer)) || !(a = NAG_ALLOC(n * n, Complex)) ||
!(af = NAG_ALLOC(n * n, Complex)) ||
!(b = NAG_ALLOC(n * nrhs, Complex)) ||
!(x = NAG_ALLOC(n * nrhs, Complex)) ||
!(berr = NAG_ALLOC(berr_len, double)) ||
!(ferr = NAG_ALLOC(ferr_len, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read A and B from data file, and copy A to AF and B to X */
scanf(" %39s%*[^\n] ", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
uplo = (Nag_UploType)nag_enum_name_to_value(nag_enum_arg);

if (uplo == Nag_Upper) {
for (i = 1; i <= n; ++i) {
for (j = i; j <= n; ++j)
scanf(" ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
}
scanf("%*[^\n] ");
} else {
for (i = 1; i <= n; ++i) {
for (j = 1; j <= i; ++j)
scanf(" ( %lf , %lf )", &A(i, j).re, &A(i, j).im);
}
scanf("%*[^\n] ");
}
for (i = 1; i <= n; ++i) {
for (j = 1; j <= nrhs; ++j)
scanf(" ( %lf , %lf )", &B(i, j).re, &B(i, j).im);
}
scanf("%*[^\n] ");
/* Copy A to AF and B to X   */
if (uplo == Nag_Upper) {
for (i = 1; i <= n; ++i) {
for (j = i; j <= n; ++j) {
AF(i, j).re = A(i, j).re;
AF(i, j).im = A(i, j).im;
}
}
} else {
for (i = 1; i <= n; ++i) {
for (j = 1; j <= i; ++j) {
AF(i, j).re = A(i, j).re;
AF(i, j).im = A(i, j).im;
}
}
}
for (i = 1; i <= n; ++i) {
for (j = 1; j <= nrhs; ++j) {
X(i, j).re = B(i, j).re;
X(i, j).im = B(i, j).im;
}
}
/* Factorize A in the array AF */
/* nag_lapacklin_zsytrf (f07nrc).
* Bunch-Kaufman factorization of complex symmetric matrix
*/
nag_lapacklin_zsytrf(order, uplo, n, af, pdaf, ipiv, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapacklin_zsytrf (f07nrc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Compute solution in the array X */
/* nag_lapacklin_zsytrs (f07nsc).
* Solution of complex symmetric system of linear equations,
* multiple right-hand sides, matrix already factorized by
* nag_lapacklin_zsytrf (f07nrc)
*/
nag_lapacklin_zsytrs(order, uplo, n, nrhs, af, pdaf, ipiv, x, pdx, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapacklin_zsytrs (f07nsc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Improve solution, and compute backward errors and */
/* estimated bounds on the forward errors */
/* nag_lapacklin_zsyrfs (f07nvc).
* Refined solution with error bounds of complex symmetric
* system of linear equations, multiple right-hand sides
*/
nag_lapacklin_zsyrfs(order, uplo, n, nrhs, a, pda, af, pdaf, ipiv, b, pdb, x,
pdx, ferr, berr, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapacklin_zsyrfs (f07nvc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Print solution */
/* nag_file_print_matrix_complex_gen_comp (x04dbc).
* Print complex general matrix (comprehensive)
*/
fflush(stdout);
nag_file_print_matrix_complex_gen_comp(
order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs, x, pdx,
Nag_BracketForm, "%7.4f", "Solution(s)", Nag_IntegerLabels, 0,
Nag_IntegerLabels, 0, 80, 0, 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_complex_gen_comp (x04dbc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
printf("\nBackward errors (machine-dependent)\n");
for (j = 1; j <= nrhs; ++j)
printf("%11.1e%s", berr[j - 1], j % 4 == 0 ? "\n" : " ");
printf("\nEstimated forward error bounds "
"(machine-dependent)\n");
for (j = 1; j <= nrhs; ++j)
printf("%11.1e%s", ferr[j - 1], j % 4 == 0 ? "\n" : " ");
printf("\n");
END:
NAG_FREE(ipiv);
NAG_FREE(a);
NAG_FREE(af);
NAG_FREE(b);
NAG_FREE(x);
NAG_FREE(berr);
NAG_FREE(ferr);
return exit_status;
}
```