/* nag_rand_int_multinomial (g05tgc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.3, 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;
}