/* nag_nonpar_randtest_gaps (g08edc) Example Program.
 *
 * Copyright 2021 Numerical Algorithms Group.
 *
 * Mark 27.3, 2021.
 *
 *
 */

#include <nag.h>
#include <stdio.h>

int main(void) {
  /* Integer scalar and array declarations */
  Integer exit_status = 0;
  Integer lstate;
  Integer *state = 0;

  /* NAG structures */
  NagError fail;

  /* Double scalar and array declarations */
  double chi, df, length, lower, p, upper, *x = 0;

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

  /* Set the seed */
  Integer seed[] = {424232};
  Integer lseed = 1;

  /* Set the size of the (randomly generated) dataset */
  Integer n = 5000;

  /* Set the maximum number of gaps (0 = no limit) */
  Integer num_gaps = 0;

  /* Set the length of the maximum gap */
  Integer max_gap = 10;

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

  printf("nag_nonpar_randtest_gaps (g08edc) Example Program Results\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;
  }

  /* Allocate arrays */
  if (!(x = NAG_ALLOC(n, 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 vector of n uniform variates between 0.0 and 1.0 */
  nag_rand_dist_uniform(n, 0.0, 1.0, state, x, &fail);

  /* Set the length of interval which contains all possible values.
     The data is generated from the range 0.0 to 1.0, so length is 1.0
   */
  length = 1.0;

  /* Set lower and upper limit for the interval used for the gap test */
  lower = 0.4;
  upper = 0.6;

  /* nag_nonpar_randtest_gaps (g08edc).
   * Performs the gaps test for randomness
   */
  nag_nonpar_randtest_gaps(n, x, num_gaps, max_gap, lower, upper, length, &chi,
                           &df, &p, &fail);

  /* Display the results */
  if (fail.code != NE_NOERROR && fail.code != NE_G08ED_GAPS &&
      fail.code != NE_G08ED_FREQ_LT_ONE) {
    printf("Error from nag_nonpar_randtest_gaps (g08edc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }
  printf("\n");
  printf("Chisq = %10.4f\n", chi);
  printf("DF    = %7.1f\n", df);
  printf("Prob  = %10.4f\n", p);
  if (fail.code == NE_G08ED_FREQ_LT_ONE)
    printf("Error from nag_nonpar_randtest_gaps (g08edc).\n%s\n", fail.message);

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

  return exit_status;
}