/* nag_chi_sq_2_way_table (g11aac) Example Program.
 *
 * Copyright 1996 Numerical Algorithms Group.
 *
 * Mark 4, 1996.
 * Mark 8 revised, 2004.
 *
 */

#include <nag.h>
#include <nagx04.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nagg11.h>

#define EXPT(I, J)  expt[(I) *tdnobs + J]
#define CHIST(I, J) chist[(I) *tdnobs + J]
#define NOBST(I, J) nobst[(I) *tdnobs + J]
int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;

  Integer  exit_status = 0, i, j, ncol, *nobst = 0, nrow, tdnobs;
  NagError fail;
  double   chi, *chist = 0, df, *expt = 0, g, prob;

  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);
  fprintf(fpout, "nag_chi_sq_2_way_table (g11aac) Example Program Results\n\n");

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n] ");

  fscanf(fpin, "%ld %ld %*[^\n] ", &nrow, &ncol);
  if (nrow >= 2 && ncol >= 2)
    {
      if (!(expt = NAG_ALLOC((nrow)*(ncol), double)) ||
          !(chist = NAG_ALLOC((nrow)*(ncol), double)) ||
          !(nobst = NAG_ALLOC((nrow)*(ncol), Integer)))
        {
          fprintf(fpout, "Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tdnobs = ncol;
    }
  else
    {
      fprintf(fpout, "Invalid nrow or ncol.\n");
      exit_status = 1;
      return exit_status;
    }
  for (i = 0; i < nrow; ++i)
    {
      for (j = 0; j < ncol; ++j)
        fscanf(fpin, "%ld", &NOBST(i, j));
      fscanf(fpin, "%*[^\n]");
    }

  /* nag_chi_sq_2_way_table (g11aac).
   * chi^2 statistics for two-way contingency table
   */
  nag_chi_sq_2_way_table(nrow, ncol, nobst, tdnobs, expt,
                         chist, &prob, &chi, &g, &df, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_chi_sq_2_way_table (g11aac).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  fprintf(fpout, "Probability = %6.4f\n", prob);
  fprintf(fpout, "Pearson Chi-square statistic = %8.3f\n", chi);
  fprintf(fpout, "Likelihood ratio test statistic = %8.3f\n", g);
  fprintf(fpout, "Degrees of freedom = %4.0f\n", df);
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (expt) NAG_FREE(expt);
  if (chist) NAG_FREE(chist);
  if (nobst) NAG_FREE(nobst);
  return exit_status;
}