/* nag_nonpar_randtest_runs (g08eac) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.2, 2024.
 *
 */

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

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

  /* NAG structures */
  NagError fail;

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

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

  /* Set the seed */
  Integer seed[] = {324213};
  Integer lseed = 1;

  /* Set the size of the (randomly generated) dataset */
  Integer n = 10000;

  /* Set the length of the longest run */
  Integer max_run = 6;

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

  printf("nag_nonpar_randtest_runs (g08eac) 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);

  /* nag_nonpar_randtest_runs (g08eac).
   * Performs the runs up or runs down test for randomness
   */
  nag_nonpar_randtest_runs(n, x, max_run, &nruns, &chi, &df, &p, &fail);

  /* Display the results */
  if (fail.code == NE_NOERROR || fail.code == NE_G08EA_RUNS) {
    printf("\n");
    printf("Total number of runs found = %10" NAG_IFMT "\n", nruns);
    if (fail.code == NE_G08EA_RUNS)
      printf("** Note : the number of runs requested were not found.\n");
    printf("\n");
    printf("Chisq = %10.4f\n", chi);
    printf("DF    = %8.2f\n", df);
    printf("Prob  = %10.4f\n", p);
  } else {
    printf("Error from nag_nonpar_randtest_runs (g08eac).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

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

  return exit_status;
}