NAG Library Manual, Mark 30.1
Interfaces:  FL   CL   CPP   AD
```/* nag_matop_real_gen_matrix_cond_std (f01jac) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.1, 2024.
*/
#include <math.h>
#include <nag.h>

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

int main(void) {
/* Scalars */
Integer exit_status = 0;
Integer i, j, n, lda;
double conda, cond_rel, eps, norma, normfa;
/* Arrays */
double *a = 0;
char function_name[100];
/* Nag Types */
Nag_OrderType order = Nag_ColMajor;
Nag_MatFunType fun;
NagError fail;

INIT_FAIL(fail);

/* Output preamble */
printf("nag_matop_real_gen_matrix_cond_std (f01jac) ");
printf("Example Program Results\n\n");
fflush(stdout);

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

/* Read in the problem size and the required function */
scanf("%" NAG_IFMT "%99s%*[^\n]", &n, function_name);

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

/* nag_enum_name_to_value (x04nac)
* Converts Nag enum member name to value
*/
fun = (Nag_MatFunType)nag_enum_name_to_value(function_name);

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

/* Print matrix A using nag_file_print_matrix_real_gen (x04cac)
* Print real general matrix (easy-to-use)
*/
nag_file_print_matrix_real_gen(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n,
n, a, lda, "A", NULL, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_gen (x04cac)\n%s\n",
fail.message);
exit_status = 2;
goto END;
}

/* Find absolute condition number estimate using
* nag_matop_real_gen_matrix_cond_std (f01jac)
* Condition number for the exponential, logarithm, sine, cosine,
* sinh or cosh of a real matrix
*/
nag_matop_real_gen_matrix_cond_std(fun, n, a, lda, &conda, &norma, &normfa,
&fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_matop_real_gen_matrix_cond_std (f01jac)\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Print absolute condition number estimate */
printf("\nf(A) = %s(A)\n", function_name);
printf("Estimated absolute condition number is: %7.2f\n", conda);

/* nag_machine_precision (x02ajc) The machine precision  */
eps = nag_machine_precision;

/* Find relative condition number estimate */
if (normfa > eps) {
cond_rel = conda * norma / normfa;
printf("Estimated relative condition number is: %7.2f\n", cond_rel);
} else {
printf("The estimated norm of f(A) is effectively zero and so\n");
printf("the relative condition number is undefined.\n");
}

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