```/* nag_quad_md_numth_vec (d01gdc) Example Program.
*
* Copyright 2014 Numerical Algorithms Group.
*
* Mark 23, 2011.
*/

#include <stdio.h>
#include <math.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagd01.h>
#include <nagx04.h>

#ifdef __cplusplus
extern "C" {
#endif
static void NAG_CALL vecfun(Integer ndim, const double x[], double fv[],
Integer m, Nag_Comm *comm);
static void NAG_CALL vecreg(Integer ndim, const double x[], Integer j,
double c[], double d[], Integer m,
Nag_Comm *comm);
#ifdef __cplusplus
}
#endif

int main(void)
{
static double ruser[2] = {-1.0, -1.0};
Integer     exit_status = 0;
Integer     ndim;
Integer     npts, nrand;
double      err, res;
double     *vk = 0;
Nag_Boolean transform;
char        nag_enum_arg[40];
Nag_Comm comm;
NagError    fail;

INIT_FAIL(fail);

/* For communication with user-supplied functions: */
comm.user = ruser;

/* Skip heading in data file */
scanf("%*[^\n] ");
/* Input parameters */
scanf("%ld %ld %ld", &ndim, &npts, &nrand);
/* Nag_Boolean */
scanf("%39s %*[^\n] ", nag_enum_arg);
transform = (Nag_Boolean) nag_enum_name_to_value (nag_enum_arg);

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

* Multidimensional quadrature, general product region,
* number-theoretic method.
*/
nag_quad_md_numth_vec(ndim, vecfun, vecreg, npts, vk, nrand, transform, &res,
&err, &comm, &fail);
if (fail.code != NE_NOERROR)
{
fail.message);
exit_status = 1;
goto END;
}

printf("\nResult = %13.5f, standard error = %10.2e\n", res, err);

END:
NAG_FREE(vk);

return exit_status;
}

static void NAG_CALL vecfun(Integer ndim, const double x[], double fv[],
Integer m, Nag_Comm *comm)
{
Integer i, index, j;
double sum;

if (comm->user[0] == -1.0)
{
printf("(User-supplied callback vecfun, first invocation.)\n");
comm->user[0] = 0.0;
}
for (i = 0; i < m; i++)
{
sum = 0.0;
for (j = 0, index = 0; j < ndim; j++, index += m) sum += x[i + index];
fv[i] = cos(0.5 + 2.0 * sum - 4.0);
}
}

static void NAG_CALL vecreg(Integer ndim, const double x[], Integer j,
double c[], double d[], Integer m, Nag_Comm *comm)
{
Integer i;

if (comm->user[1] == -1.0)
{
printf("(User-supplied callback vecreg, first invocation.)\n");
comm->user[1] = 0.0;
}
for (i = 0; i < m; i++)
{
c[i] = 0.0;
d[i] = 1.0;
}
}
```