/* nag_prob_lin_chi_sq (g01jdc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

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

int main(int argc, char *argv[])
{
  FILE          *fpin, *fpout;
  /* Scalars */
  double        c, d, prob;
  Integer       exit_status, i, n;
  /* Arrays */
  char          nag_enum_arg[40];
  double        *rlam = 0;
  Nag_LCCMethod method;
  NagError      fail;

  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);
  exit_status = 0;
  fprintf(fpout, "nag_prob_lin_chi_sq (g01jdc) Example Program Results\n");

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n] ");
  n = 10;

  /* Allocate memory */
  if (!(rlam = NAG_ALLOC(n, double)))
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  fscanf(fpin, " %s%lf%lf%*[^\n] ", nag_enum_arg, &d, &c);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  method = (Nag_LCCMethod) nag_enum_name_to_value(nag_enum_arg);

  for (i = 1; i <= n; ++i)
    fscanf(fpin, "%lf", &rlam[i - 1]);
  fscanf(fpin, "%*[^\n] ");

  /* nag_prob_lin_chi_sq (g01jdc).
   * Computes lower tail probability for a linear combination
   * of (central) chi^2 variables
   */
  nag_prob_lin_chi_sq(method, n, rlam, d, c, &prob, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_prob_lin_chi_sq (g01jdc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  fprintf(fpout, "\n");
  fprintf(fpout, " Values of lambda ");
  for (i = 1; i <= n; ++i)
    {
      if (i%6 == 0) 
	fprintf(fpout, "%18s", " ");

      fprintf(fpout, "%6.2f ", rlam[i - 1]);

      if (i%5 == 0 || i == n) 
	  fprintf(fpout, "\n");
    }
  fprintf(fpout, " Value of D       %6.2f\n", d);
  fprintf(fpout, " Value of C       %6.2f\n\n", c);
  fprintf(fpout, " Probability = %11.4f\n", prob);

 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (rlam) NAG_FREE(rlam);

  return exit_status;
}