NAG Library Manual, Mark 28.3
```/* nag_matop_complex_gen_matrix_sqrt (f01fnc) Example Program.
*
* Copyright 2022 Numerical Algorithms Group.
*
* Mark 28.3, 2022.
*/
#include <math.h>
#include <nag.h>

#define A(I, J) a[J * pda + I]

int main(void) {

/* Scalars */
Integer exit_status = 0;
Integer i, j, n, pda;
/* Arrays */
Complex *a = 0;
/* Nag Types */
Nag_OrderType order = Nag_ColMajor;
NagError fail;

INIT_FAIL(fail);

/* Output preamble */
printf("nag_matop_complex_gen_matrix_sqrt (f01fnc) ");
printf("Example Program Results\n\n");
fflush(stdout);

/* Skip heading in data file */
scanf("%*[^\n] ");

/* Read in the problem size */
scanf("%" NAG_IFMT "%*[^\n]", &n);

pda = n;
if (!(a = NAG_ALLOC(pda * n, Complex))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read in the matrix A from data file */
for (i = 0; i < n; i++) {
for (j = 0; j < n; j++) {
scanf(" ( %lf , %lf ) ", &A(i, j).re, &A(i, j).im);
}
}
scanf("%*[^\n] ");

/* Find the matrix square root using
* nag_matop_complex_gen_matrix_sqrt (f01fnc)
* Complex matrix square root
*/
nag_matop_complex_gen_matrix_sqrt(n, a, pda, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_matop_complex_gen_matrix_sqrt (f01fnc)\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Print matrix sqrt(A) using
* nag_file_print_matrix_complex_gen (x04dac)
* Print complex general matrix (easy-to-use)
*/
nag_file_print_matrix_complex_gen(order, Nag_GeneralMatrix, Nag_NonUnitDiag,
n, n, a, pda, "sqrt(A)", NULL, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_complex_gen (x04dac)\n%s\n",
fail.message);
exit_status = 2;
goto END;
}

END:
NAG_FREE(a);
return exit_status;
}
```