NAG Library Manual, Mark 27.3
```/* nag_rand_copula_gumbel (g05rkc) Example Program.
*
* Copyright 2021 Numerical Algorithms Group.
*
* Mark 27.3, 2021.
*/
/* Pre-processor includes */
#include <math.h>
#include <nag.h>
#include <stdio.h>

#define X(I, J)                                                                \
x[order == Nag_ColMajor ? ((J - 1) * pdx + I - 1) : ((I - 1) * pdx + J - 1)]

int main(void) {
/* Integer scalar and array declarations */
Integer exit_status = 0;
Integer i, j, lstate, pdx, sdx;
Integer *state = 0;

/* Double scalar and array declarations */
double *x = 0;

/* NAG structures */
NagError fail;

/* Use row major order */
Nag_OrderType order = Nag_RowMajor;

/* Set the number of variables and variates */
Integer n = 13, m = 4;

/* Choose the base generator */
Nag_BaseRNG genid = Nag_Basic;
Integer subid = 0;

/* Set the seed */
Integer seed[] = {1762543};
Integer lseed = 1;

/* Set the theta parameter value */
double theta = 2.4e0;

/* Initialize the error structure */
INIT_FAIL(fail);

printf("nag_rand_copula_gumbel (g05rkc) Example Program Results\n\n");

/* Get the length of the state array */
lstate = -1;
nag_rand_init_repeat(genid, subid, seed, lseed, state, &lstate, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_rand_init_repeat (g05kfc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Set matrix size and principal dimension according to storage order */
pdx = (order == Nag_ColMajor) ? n : m;
sdx = (order == Nag_ColMajor) ? m : n;

/* Allocate arrays */
if (!(x = NAG_ALLOC((pdx * sdx), double)) ||
!(state = NAG_ALLOC(lstate, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Initialize the generator to a repeatable sequence */
nag_rand_init_repeat(genid, subid, seed, lseed, state, &lstate, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_rand_init_repeat (g05kfc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Generate variates */
nag_rand_copula_gumbel(order, state, theta, n, m, x, pdx, sdx, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_rand_copula_gumbel (g05rkc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Display the results */
printf("Uniform variates with copula joint distrbution\n");
for (i = 1; i <= n; i++) {
printf("  ");
for (j = 1; j <= m; j++)
printf("%9.6f%s", X(i, j), j < m ? " " : "\n");
}

END:
NAG_FREE(x);
NAG_FREE(state);

return exit_status;
}
```