/* nag_pairs_test (g08ebc) Example Program.
 *
 * Copyright 2017 Numerical Algorithms Group.
 *
 * Mark 26.2, 2017.
 *
 *
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg05.h>
#include <nagg08.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, p;
  double *x = 0;

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

  /* Set the seed */
  Integer seed[] = { 438532 };
  Integer lseed = 1;

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

  /* Set the size of the matrix of counts */
  Integer max_count = 10;

  /* Set the lag used when choosing pairs */
  Integer lag = 1;

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

  printf("nag_pairs_test (g08ebc) Example Program Results\n");

  /* Get the length of the state array */
  lstate = -1;
  nag_rand_init_repeatable(genid, subid, seed, lseed, state, &lstate, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_rand_init_repeatable (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_repeatable(genid, subid, seed, lseed, state, &lstate, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_rand_init_repeatable (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_basic(n, state, x, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_rand_basic (g05sac).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /* nag_pairs_test (g08ebc).
   * Performs the pairs (serial) test for randomness
   */
  nag_pairs_test(n, x, max_count, lag, &chi, &df, &p, &fail);

  if (fail.code != NE_NOERROR && fail.code != NE_G08EB_CELL) {
    printf("Error from nag_pairs_test (g08ebc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  /* Display the results */
  printf("\n");
  printf("\n");
  printf("%s%10.4f\n", "CHISQ          = ", chi);
  printf("%s%8.2f\n", "DF             = ", df);
  printf("%s%10.4f\n", "Probability    = ", p);
  if (fail.code == NE_G08EB_CELL)
    printf("Error from nag_pairs_test (g08ebc).\n%s\n", fail.message);

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

  return exit_status;
}