/* nag_rand_leap_frog (g05khc) Example Program.
 *
 * Copyright 2008, Numerical Algorithms Group.
 *
 * Mark 9, 2009.
 */
/* Pre-processor includes */
#include <stdio.h>
#include <math.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg05.h>

#define STATE(I, J) state[(J - 1)*lstate + I - 1]

int main(void)
{
  /* Integer scalar and array declarations */
  Integer     exit_status = 0;
  Integer     i, j, lstate;
  Integer     *state = 0;
  /* NAG structures */
  NagError    fail;
  /* Double scalar and array declarations */
  double      *x = 0;
  /* Set the sample size */
  Integer     nv = 5;
  /* Set the number of streams */
  Integer     n = 3;
  /* Choose the base generator */
  Nag_BaseRNG genid = Nag_Basic;
  Integer     subid = 0;
  /* Set the seed */
  Integer     seed[] = { 1762543 };
  Integer     lseed = 1;

  /* Initialise the error structure */
  INIT_FAIL(fail);

  printf("nag_rand_leap_frog (g05khc) Example Program Results\n\n");

  /* Get the length of the state array */
  lstate = -1;
  nag_rand_init_repeatable(genid, subid, seed, lseed, state, &lstate, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_rand_init_repeatable (g05kfc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* Allocate arrays */
  if (!(x = NAG_ALLOC(nv, double)) ||
      !(state = NAG_ALLOC(lstate*n, Integer)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* Prepare n streams */
  for (i = 1; i <= n; i++)
    {
      /* Initialise the I'th stream to a repeatable sequence, using the same
         seed for each stream */
      nag_rand_init_repeatable(genid, subid, seed, lseed, &STATE(1, i),
                               &lstate, &fail);
      if (fail.code != NE_NOERROR)
        {
          printf("Error from nag_rand_init_repeatable (g05kfc).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }

      /* Prepare the I'th out of N streams*/
      nag_rand_leap_frog(n, i, &STATE(1, i), &fail);
      if (fail.code != NE_NOERROR)
        {
          printf("Error from nag_rand_leap_frog (g05khc).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
    }

  /* Loop over each of the n streams */
  for (i = 1; i <= n; i++)
    {
      /* Generate nv variates from a univariate distribution */
      printf(" Stream %12ld\n", i);
      nag_rand_basic(nv, &STATE(1, i), x, &fail);
      if (fail.code != NE_NOERROR)
        {
          printf("Error from nag_rand_basic (g05sac).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }

      /* Display the variates*/
      for (j = 0; j < nv; j++)
        printf("%11.4f\n", x[j]);
      printf(" \n");
    }

 END:
  if (x) NAG_FREE(x);
  if (state) NAG_FREE(state);

  return exit_status;
}