NAG Library Manual, Mark 28.6
```/* nag_matop_complex_gen_matrix_log (f01fjc) Example Program.
*
* Copyright 2022 Numerical Algorithms Group.
*
* Mark 28.6, 2022.
*/

#include <nag.h>

int main(void) {

/* Scalars */
Integer exit_status = 0;
Integer i, j, n, pda;

/* Arrays */
Complex *a = 0;

/* Nag Types */
Nag_OrderType order;
NagError fail;

INIT_FAIL(fail);

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
order = Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 1]
order = Nag_RowMajor;
#endif

/* Output preamble */
printf("nag_matop_complex_gen_matrix_log (f01fjc) ");
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 = 1; i <= n; i++)
for (j = 1; j <= n; j++)
scanf(" ( %lf , %lf ) ", &A(i, j).re, &A(i, j).im);
scanf("%*[^\n]");

/* Find log(A) using
* nag_matop_complex_gen_matrix_log (f01fjc)
* Complex matrix logarithm
*/
nag_matop_complex_gen_matrix_log(order, n, a, pda, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_matop_complex_gen_matrix_log (f01fjc)\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Print solution 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, n, "log(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;
}
```