/* nag_nonpar_test_chisq (g08cgc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.3, 2024.
 *
 *
 */

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

int main(void) {
  /* Integer scalar and array declarations */
  Integer exit_status = 0, i, n, nclass, ndf, npest, lstate;
  Integer *ifreq = 0, *state = 0;

  /* NAG structures */
  Nag_ClassBoundary classb;
  Nag_Distributions cdist;
  NagError fail;

  /* Double scalar and array declarations */
  double chisq, *chisqi = 0, *cint = 0, *eval = 0, p, *par = 0;
  double *prob = 0, *x = 0, xmax, xmin;

  /* Character array declarations */
  char nag_enum_arg[40];

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

  /* Set the seed */
  Integer seed[] = {1762543};
  Integer lseed = 1;

  INIT_FAIL(fail);

  printf("nag_nonpar_test_chisq (g08cgc) 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;
  }

  /* Skip heading in data file */
  scanf("%*[^\n]");
  scanf("%" NAG_IFMT " %" NAG_IFMT "  %39s %*[^\n] ", &n, &nclass,
        nag_enum_arg);

  /* nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  cdist = (Nag_Distributions)nag_enum_name_to_value(nag_enum_arg);

  if (!(x = NAG_ALLOC(n, double)) || !(state = NAG_ALLOC(lstate, Integer)) ||
      !(cint = NAG_ALLOC(nclass - 1, double)) ||
      !(par = NAG_ALLOC(2, double)) || !(ifreq = NAG_ALLOC(nclass, Integer))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  for (i = 1; i <= 2; ++i)
    scanf("%lf", &par[i - 1]);
  npest = 0;

  /* 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 random numbers from a uniform distribution */
  nag_rand_dist_uniform(n, par[0], par[1], state, x, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_rand_dist_uniform (g05sqc).\n%s\n", fail.message);
    return 1;
  }

  classb = Nag_ClassBoundaryComp;
  /* Determine suitable intervals */
  if (cdist == Nag_Uniform) {
    classb = Nag_ClassBoundaryUser;
    cint[0] = par[0] + (par[1] - par[0]) / nclass;
    for (i = 2; i <= nclass - 1; ++i)
      cint[i - 1] = cint[i - 2] + (par[1] - par[0]) / nclass;
  }

  /* nag_stat_frequency_table (g01aec).
   * Frequency table from raw data
   */
  nag_stat_frequency_table(n, x, nclass, classb, cint, ifreq, &xmin, &xmax,
                           &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_stat_frequency_table (g01aec).\n%s\n", fail.message);
    return 1;
  }

  if (!(chisqi = NAG_ALLOC(nclass, double)) ||
      !(eval = NAG_ALLOC(nclass, double)) ||
      !(prob = NAG_ALLOC(nclass, double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }
  /* nag_nonpar_test_chisq (g08cgc).
   * Performs the chi^2 goodness of fit test, for standard
   * continuous distributions
   */
  nag_nonpar_test_chisq(nclass, ifreq, cint, cdist, par, npest, prob, &chisq,
                        &p, &ndf, eval, chisqi, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_nonpar_test_chisq (g08cgc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }
  printf("\n");
  printf("%s%10.4f\n", "Chi-squared test statistic   = ", chisq);
  printf("%s%5" NAG_IFMT "\n", "Degrees of freedom.          = ", ndf);
  printf("%s%10.4f\n", "Significance level           = ", p);
  printf("\n");
  printf("%s\n", "The contributions to the test statistic are :-");
  for (i = 1; i <= nclass; ++i)
    printf("%10.4f\n", chisqi[i - 1]);
END:
  NAG_FREE(x);
  NAG_FREE(cint);
  NAG_FREE(par);
  NAG_FREE(ifreq);
  NAG_FREE(chisqi);
  NAG_FREE(eval);
  NAG_FREE(prob);
  NAG_FREE(state);
  return exit_status;
}