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|
(* TEST
*)
(***
This test evaluate boolean formula composed by conjunction and
disjunction using ephemeron:
- true == alive, false == garbage collected
- and == an n-ephemeron, or == many 1-ephemeron
*)
let nb_test = 4
let max_level = 10
(** probability that a branch is not linked to a previous one *)
let proba_no_shared = 0.2
let arity_max = 4
let proba_new = proba_no_shared ** (1./.(float_of_int max_level))
open Format
open Ephemeron
let is_true test s b = printf "%s %s: %s\n" test s (if b then "OK" else "FAIL")
let is_false test s b = is_true test s (not b)
type varephe = int ref
type ephe = (varephe,varephe) Kn.t
type formula =
| Constant of bool
| And of var array
| Or of var array
and var = {
form: formula;
value: bool;
ephe: varephe Weak.t;
}
let print_short_bool fmt b =
if b
then pp_print_string fmt "t"
else pp_print_string fmt "f"
let rec pp_form fmt = function
| Constant b ->
fprintf fmt "%B" b
| And a ->
fprintf fmt "And[@[%a@]]" (fun fmt -> Array.iter (pp_var fmt)) a
| Or a ->
fprintf fmt "Or[@[%a@]]" (fun fmt -> Array.iter (pp_var fmt)) a
and pp_var fmt v =
fprintf fmt "%a%a:%a;@ "
print_short_bool v.value
print_short_bool (Weak.check v.ephe 0)
pp_form v.form
type env = {
(** resizable array for cheap *)
vars : (int,var) Hashtbl.t;
(** the ephemerons must be alive *)
ephes : ephe Stack.t;
(** keep alive the true constant *)
varephe_true : varephe Stack.t;
(** keep temporarily alive the false constant *)
varephe_false : varephe Stack.t;
}
let new_env () = {
vars = Hashtbl.create 100;
ephes = Stack.create ();
varephe_true = Stack.create ();
varephe_false = Stack.create ();
}
let evaluate = function
| Constant b -> b
| And a -> Array.fold_left (fun acc e -> acc && e.value) true a
| Or a -> Array.fold_left (fun acc e -> acc || e.value) false a
let get_ephe v =
match Weak.get v.ephe 0 with
| None ->
invalid_arg "Error: weak dead but nothing have been released"
| Some r -> r
(** create a variable and its definition in the boolean world and
ephemerons world *)
let rec create env rem_level (** remaining level *) =
let varephe = ref 1 in
let form =
if rem_level = 0 then (** Constant *)
if Random.bool ()
then (Stack.push varephe env.varephe_true ; Constant true )
else (Stack.push varephe env.varephe_false; Constant false)
else
let size = (Random.int (arity_max - 1)) + 2 in
let new_link _ =
if (Hashtbl.length env.vars) = 0 || Random.float 1. < proba_new
then create env (rem_level -1)
else Hashtbl.find env.vars (Random.int (Hashtbl.length env.vars))
in
let args = Array.init size new_link in
if Random.bool ()
then begin (** Or *)
Array.iter (fun v ->
let r = get_ephe v in
let e = Kn.create 1 in
Kn.set_key e 0 r;
Kn.set_data e varephe;
Stack.push e env.ephes
) args; Or args
end
else begin (** And *)
let e = Kn.create (Array.length args) in
for i=0 to Array.length args - 1 do
Kn.set_key e i (get_ephe args.(i));
done;
Kn.set_data e varephe;
Stack.push e env.ephes;
And args
end
in
let create_weak e =
let w = Weak.create 1 in
Weak.set w 0 (Some e);
w
in
let v = {form; value = evaluate form;
ephe = create_weak varephe;
} in
Hashtbl.add env.vars (Hashtbl.length env.vars) v;
v
let check_var v = v.value = Weak.check v.ephe 0
let run test init =
Random.init init;
let env = new_env () in
let _top = create env max_level in
(** release false ref *)
Stack.clear env.varephe_false;
Gc.full_major ();
let res = Hashtbl.fold (fun _ v acc -> acc && check_var v) env.vars true in
is_true test "check" res;
env (* Keep env.varephe_true alive. *)
let () =
for i = 0 to nb_test do
ignore (run ("test"^(Int.to_string i)) i);
done
|
