/* nag_prob_non_central_chi_sq (g01gcc) Example Program.
 *
 * Copyright 1999 Numerical Algorithms Group.
 *
 * Mark 6a revised, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nagg01.h>

int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;
  Integer  exit_status = 0, max_iter;
  NagError fail;
  double   df, lambda, prob, tol, x;

  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_prob_non_central_chi_sq (g01gcc) Example Program Results\n\n");

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

  fprintf(fpout, "\n     x       df      lambda   prob\n\n\n");
  tol = 5e-6;
  max_iter = 50;
  while ((fscanf(fpin, " %lf %lf %lf %*[^\n] ", &x, &df, &lambda)) != EOF)
    {
      /* nag_prob_non_central_chi_sq (g01gcc).
       * Computes probabilities for the non-central chi^2
       * distribution
       */
      prob = nag_prob_non_central_chi_sq(x, df, lambda, tol, max_iter, &fail);
      if (fail.code != NE_NOERROR)
        {
          fprintf(fpout,
                  "Error from nag_prob_non_central_chi_sq (g01gcc).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
      fprintf(fpout, "%8.3f %8.3f %8.3f %8.4f\n", x, df, lambda, prob);
    }
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  return exit_status;
}