/* nag_rand_int_multinomial (g05tgc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.2, 2024.
*/
/* Pre-processor includes */
#include <math.h>
#include <nag.h>
#include <stdio.h>
#define X(I, J) x[(order == Nag_ColMajor) ? (J * pdx + I) : (I * pdx + J)]
int main(void) {
/* Integer scalar and array declarations */
Integer exit_status = 0;
Integer lr, x_size, i, j, lstate, pdx;
Integer *state = 0, *x = 0;
/* NAG structures */
NagError fail;
Nag_ModeRNG mode;
/* Double scalar and array declarations */
double p_max;
double *r = 0;
/* Set the distribution parameters */
Integer k = 4;
Integer m = 6000;
double p[] = {0.08e0, 0.1e0, 0.8e0, 0.02e0};
/* Set the sample size */
Integer n = 20;
/* Return the results in column major order */
Nag_OrderType order = Nag_ColMajor;
/* Choose the base generator */
Nag_BaseRNG genid = Nag_Basic;
Integer subid = 0;
/* Set the seed */
Integer seed[] = {1762543};
Integer lseed = 1;
/* Initialize the error structure */
INIT_FAIL(fail);
printf("nag_rand_int_multinomial (g05tgc) 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;
}
pdx = (order == Nag_ColMajor) ? n : k;
x_size = (order == Nag_ColMajor) ? pdx * k : pdx * n;
/* Calculate the size of the reference vector */
p_max = 0.0;
for (i = 1; i < k; i++)
p_max = (p_max < p[i]) ? p[i] : p_max;
lr = 30 + 20 * sqrt(m * p_max * (1 - p_max));
/* Allocate arrays */
if (!(r = NAG_ALLOC(lr, double)) || !(state = NAG_ALLOC(lstate, Integer)) ||
!(x = NAG_ALLOC(x_size, 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 the variates, initializing the reference vector
at the same time */
mode = Nag_InitializeAndGenerate;
nag_rand_int_multinomial(order, mode, n, m, k, p, r, lr, state, x, pdx,
&fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_rand_int_multinomial (g05tgc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Display the variates */
for (i = 0; i < n; i++) {
for (j = 0; j < k; j++)
printf("%12" NAG_IFMT "", X(i, j));
printf("\n");
}
END:
NAG_FREE(r);
NAG_FREE(state);
NAG_FREE(x);
return exit_status;
}