[Icfp04-discuss] Unofficial Tournament

[Eijiro Sumii]

From: "Rares Ispas" <rares at raisoftware.ro>
> Vox populi, vox Dei. If 10 people express their desire to work on  
> next-generation ants, we will revive the tournament. Open only for ants  
> not submitted to ICFP.

As Benjamin mentioned, even we organizers may submit some of our own
ants if people don't mind!

By the way, I remember the tournament web page used to mention it does
_not_ implement the same random number generation as described in the
task description.  For reference, here is an implementation in C
(dependent on >= 31-bit int):

/**********************************************************************/
static int seed = 0;

void mysrand(int s) {
  printf("random seed: %d\n", s);
  seed = s;
  (void) myrand();
  (void) myrand();
  (void) myrand();
}

int myrand() {
  int r;
  seed = seed * 22695477 + 1;
  r = (seed >> 16) & 0x3fff;
  /* printf("random number: %d\n", r); */
  return r;
}
/**********************************************************************/

And in OCaml (also dependent on >= 31-bit int):

(**********************************************************************)
let seed = ref 0

let int p =
  seed := !seed * 22695477 + 1;
  let r = (!seed asr 16) land 0x3fff in
  (* Format.eprintf "random number: %d at ." r; *)
  r mod p

let init s =
  Format.eprintf "random seed: %d at ." s;
  seed := s;
  ignore(int 1);
  ignore(int 1);
  ignore(int 1)
(**********************************************************************)

Have fun,

--
Eijiro Sumii (http://www.cis.upenn.edu/~sumii/)
Department of Computer and Information Science, University of Pennsylvania