NAG Library Manual, Mark 29.3
```/* nag_sparse_direct_real_gen_norm (f11mlc) Example Program.
*
* Copyright 2023 Numerical Algorithms Group.
*
* Mark 29.3, 2023.
*/

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

int main(void) {
double anorm;
Integer exit_status = 0, i, n, nnz;
double *a = 0;
Integer *icolzp = 0, *irowix = 0;
/* Nag types */
Nag_NormType norm;
NagError fail;

INIT_FAIL(fail);

printf(
"nag_sparse_direct_real_gen_norm (f11mlc) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n] ");
/* Read order of matrix and number of right hand sides */
scanf("%" NAG_IFMT "%*[^\n] ", &n);
/* Read the matrix A */
if (!(icolzp = NAG_ALLOC(n + 1, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 1; i <= n + 1; ++i)
scanf("%" NAG_IFMT "%*[^\n] ", &icolzp[i - 1]);
nnz = icolzp[n] - 1;
/* Allocate memory */
if (!(a = NAG_ALLOC(nnz, double)) || !(irowix = NAG_ALLOC(nnz, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 1; i <= nnz; ++i)
scanf("%lf%" NAG_IFMT "%*[^\n] ", &a[i - 1], &irowix[i - 1]);
/* Calculate 1-norm */
norm = Nag_RealOneNorm;
/* nag_sparse_direct_real_gen_norm (f11mlc).
* 1-norm, infinity-norm, largest absolute element, real
* general matrix
*/
nag_sparse_direct_real_gen_norm(norm, &anorm, n, icolzp, irowix, a, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sparse_direct_real_gen_norm (f11mlc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Output norm */
printf("%s\n%7.3f\n", "One-norm", anorm);

/* Calculate M-norm */
norm = Nag_RealMaxNorm;
/* nag_sparse_direct_real_gen_norm (f11mlc), see above. */
nag_sparse_direct_real_gen_norm(norm, &anorm, n, icolzp, irowix, a, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sparse_direct_real_gen_norm (f11mlc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Output norm */
printf("\n");
printf("%s\n%7.3f\n", "Max", anorm);

/* Calculate I-norm */
norm = Nag_RealInfNorm;
/* nag_sparse_direct_real_gen_norm (f11mlc), see above. */
nag_sparse_direct_real_gen_norm(norm, &anorm, n, icolzp, irowix, a, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sparse_direct_real_gen_norm (f11mlc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Output norm */
printf("\n");
printf("%s\n%7.3f\n", "Infinity-norm", anorm);

END:
NAG_FREE(a);
NAG_FREE(icolzp);
NAG_FREE(irowix);

return exit_status;
}
```