/* 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 <nag_stdlib.h>
#include <nagg01.h>

int main(void)
{

  /* Scalars */
  double c, d, prob;
  Integer exit_status, i, n;

  /* Arrays */
  char *method=0;
  double *rlam=0;

  Nag_LCCMethod method_enum;
  NagError fail;

  INIT_FAIL(fail);
  exit_status = 0;
  Vprintf("nag_prob_lin_chi_sq (g01jdc) Example Program Results\n");

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

  /* Allocate memory */
  if ( !(method = NAG_ALLOC(2, char)) ||
       !(rlam = NAG_ALLOC(n, double)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  Vscanf(" ' %1s '%lf%lf%*[^\n] ", method, &d, &c);
  for (i = 1; i <= n; ++i)
    Vscanf("%lf", &rlam[i - 1]);
  Vscanf("%*[^\n] ");

  if (!(strcmp(method, "P")))
    method_enum =  Nag_LCCPan;
  else if (!(strcmp(method, "I")))
    method_enum = Nag_LCCImhof;
  else if (!(strcmp(method, "D")))
    method_enum = Nag_LCCDefault;
  else
    {
      Vprintf("The character `method' is invalid\n");
      exit_status = -1;
      goto END;
    }

  /* 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_enum, n, rlam, d, c, &prob, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_prob_lin_chi_sq (g01jdc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;

    }

  Vprintf("\n");
  Vprintf("Values of lambda ");
  for (i = 1; i <= n; ++i)
    {
      Vprintf("%6.2f", rlam[i - 1]);

      Vprintf(i%10 == 0 || i == 10 ?"\n":" ");
    }
  Vprintf(" Value of D       %6.2f\n", d);
  Vprintf(" Value of C       %6.2f\n\n", c);
  Vprintf(" Probability = %10.4f\n", prob);

 END:
  if (method) NAG_FREE(method);
  if (rlam) NAG_FREE(rlam);

  return exit_status;
}