```/* nag_zpbcon (f07huc) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.2, 2017.
*/

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <naga02.h>
#include <nagf07.h>
#include <nagf16.h>
#include <nagx02.h>

int main(void)
{
/* Scalars */
Integer i, j, k, kd, n, pdab;
Integer exit_status = 0;
double anorm, rcond;
NagError fail;
Nag_UploType uplo;
Nag_OrderType order;
/* Arrays */
char nag_enum_arg[40];
Complex *ab = 0;

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

INIT_FAIL(fail);

printf("nag_zpbcon (f07huc) Example Program Results\n\n");

/* Skip heading in data file */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &n, &kd);
pdab = kd + 1;

/* Allocate memory */
if (!(ab = NAG_ALLOC((kd + 1) * n, Complex)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read A from data file */
scanf(" %39s%*[^\n] ", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg);

k = kd + 1;
if (uplo == Nag_Upper) {
for (i = 1; i <= n; ++i) {
for (j = i; j <= MIN(i + kd, n); ++j) {
scanf(" ( %lf , %lf )", &AB_UPPER(i, j).re, &AB_UPPER(i, j).im);
}
}
scanf("%*[^\n] ");
}
else {
for (i = 1; i <= n; ++i) {
for (j = MAX(1, i - kd); j <= i; ++j) {
scanf(" ( %lf , %lf )", &AB_LOWER(i, j).re, &AB_LOWER(i, j).im);
}
}
scanf("%*[^\n] ");
}
/* Compute norm of A */
/* nag_zhb_norm (f16uec).
* 1-norm, infinity-norm, Frobenius norm, largest absolute
* element, complex Hermitian band matrix
*/
nag_zhb_norm(order, Nag_OneNorm, uplo, n, kd, ab, pdab, &anorm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_zhb_norm (f16uec).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Factorize A */
/* nag_zpbtrf (f07hrc).
* Cholesky factorization of complex Hermitian
* positive-definite band matrix
*/
nag_zpbtrf(order, uplo, n, kd, ab, pdab, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_zpbtrf (f07hrc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Estimate condition number */
/* nag_zpbcon (f07huc).
* Estimate condition number of complex Hermitian
* positive-definite band matrix, matrix already factorized
* by nag_zpbtrf (f07hrc)
*/
nag_zpbcon(order, uplo, n, kd, ab, pdab, anorm, &rcond, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_zpbcon (f07huc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* nag_machine_precision (x02ajc).
* The machine precision
*/
if (rcond >= nag_machine_precision)
printf("Estimate of condition number =%11.2e\n\n", 1.0 / rcond);
else
printf("A is singular to working precision\n");
END:
NAG_FREE(ab);
return exit_status;
}
```