NAG Library Manual, Mark 28.3
```/* nag_blast_dgb_norm (f16rbc) Example Program.
*
* Copyright 2022 Numerical Algorithms Group.
*
* Mark 28.3, 2022.
*/

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

int main(void) {

/* Scalars */
double r_one, r_inf, r_f, r_max;
Integer ab_size, exit_status, i, j, kl, ku;
Integer m, n, pdab;

/* Arrays */
double *ab = 0;

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

#ifdef NAG_COLUMN_MAJOR
#define AB(I, J) ab[(J - 1) * pdab + ku + I - J]
order = Nag_ColMajor;
#else
#define AB(I, J) ab[(I - 1) * pdab + kl + J - I]
order = Nag_RowMajor;
#endif

exit_status = 0;
INIT_FAIL(fail);

printf("nag_blast_dgb_norm (f16rbc) Example Program Results\n\n");

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

/* Read the problem dimensions */
scanf("%" NAG_IFMT "%" NAG_IFMT "%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &m, &n,
&kl, &ku);

pdab = kl + ku + 1;
#ifdef NAG_COLUMN_MAJOR
ab_size = pdab * n;
#else
ab_size = pdab * m;
#endif

if (m > 0 && n > 0) {
/* Allocate memory */
if (!(ab = NAG_ALLOC(ab_size, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
} else {
printf("Invalid m or n\n");
exit_status = 1;
return exit_status;
}

/* Input matrix A. */

for (i = 1; i <= m; ++i) {
for (j = MAX(1, i - kl); j <= MIN(n, i + ku); ++j)
scanf("%lf", &AB(i, j));
scanf("%*[^\n] ");
}

/* nag_blast_dgb_norm (f16rbc).
* calculates norm of real valued general band matrix.
*
*/
nag_blast_dgb_norm(order, Nag_OneNorm, m, n, kl, ku, ab, pdab, &r_one, &fail);

if (fail.code != NE_NOERROR)
goto GB_FAIL;

nag_blast_dgb_norm(order, Nag_InfNorm, m, n, kl, ku, ab, pdab, &r_inf, &fail);

if (fail.code != NE_NOERROR)
goto GB_FAIL;

nag_blast_dgb_norm(order, Nag_FrobeniusNorm, m, n, kl, ku, ab, pdab, &r_f,
&fail);

if (fail.code != NE_NOERROR)
goto GB_FAIL;

nag_blast_dgb_norm(order, Nag_MaxNorm, m, n, kl, ku, ab, pdab, &r_max, &fail);

if (fail.code != NE_NOERROR)
goto GB_FAIL;

/* Print norms of A. */
printf(" Norms of banded matrix A:\n\n");
printf(" One norm       = %7.4f\n", r_one);
printf(" Infinity norm  = %7.4f\n", r_inf);
printf(" Frobenius norm = %7.4f\n", r_f);
printf(" Maximum norm   = %7.4f\n", r_max);
goto END;

GB_FAIL:
printf("Error from nag_blast_dgb_norm.\n%s\n", fail.message);
exit_status = 1;

END:
NAG_FREE(ab);

return exit_status;
}
```