_____
Von: Tom [mailto:tom.primozic@gmail.com]
Gesendet: Mittwoch, 26. Juli 2006 15:53
An: Christoph Bauer
Betreff: Re: [Caml-list] generic Hashtbl.to_array
Once again...
I'm sorry to say that, but I believe that you results are flawed...
Upon inspecting your code with Toploop, I found out some flaws...
let h n =
let m = n * 100000 in
let h = Hashtbl.create m in
for i = 0 to m - 1 do (* <<< not Hashtbl.length h, as it returns 0
for ampty hashtable *)
Hashtbl.replace h (Random.int max_int) (
Random.int max_int);
done;
h
thanks, sorry for this stupid bug. to_array_5 is now the clear winner.
Christoph Bauer
n=8
Rate to_array_2 to_array_3 to_array_1c to_array_1
to_array_4 to_array_1b to_array_5
to_array_2 34.6+-0.4/s -- -50% -71% -72%
-74% -74% -79%
to_array_3 68.8+-0.6/s 99% -- -42% -45%
-49% -49% -58%
to_array_1c 118+- 2/s 241% 71% -- -6%
-12% -13% -27%
to_array_1 126+- 0/s 264% 83% 7% --
-6% -7% -22%
to_array_4 134+- 2/s 287% 95% 14% 6%
-- [-1%] -17%
to_array_1b 135+- 1/s 290% 96% 15% 7%
[1%] -- -17%
to_array_5 162+- 10/s 369% 136% 37% 29%
21% 20% --
(* compile with
ocamlopt -o to_array -I benchmark-0.7 unix.cmxa benchmark-0.7/benchmark.cmx
to_array.ml
*)
open Benchmark
let to_array_1 t =
let dummy = Array.init 0 (fun _ -> raise Not_found) in
fst
(Hashtbl.fold
(fun k v (a, i) ->
if i = 0 then
let a = Array.make (Hashtbl.length t) (k, v) in
(a, 1)
else (a.(i) <- (k, v); (a, i + 1)))
t (dummy, 0))
let to_array_2 t =
let init _ = fun () -> raise Not_found in
let a = Array.init (Hashtbl.length t) init in
ignore
(Hashtbl.fold (fun k v i -> a.(i) <- (fun () -> (k, v)); i+1) t 0);
Array.map (fun f -> f ()) a
let to_array_3 t =
Array.of_list (Hashtbl.fold (fun a b c -> (a, b) :: c) t [])
let to_array_1b t =
let a = ref (Array.init 0 (fun _ -> raise Not_found)) in
ignore
(Hashtbl.fold
(fun k v i ->
if i = 0 then
(a := Array.make (Hashtbl.length t) (k, v);
1)
else
((!a).(i) <- (k, v); i + 1))
t 0);
!a
let to_array_4 t =
let init = ref None in
begin try Hashtbl.iter (fun k v -> init := Some (k,v); raise Exit) t
with Exit -> ()
end;
match !init with
| None -> [| |]
| Some i ->
let a = Array.make (Hashtbl.length t) i in
ignore (Hashtbl.fold (fun k v i -> a.(i) <- (k, v); i + 1) t 0);
a
let to_array_5 =
let init = Obj.magic 0 in
fun t ->
let a = Array.make (Hashtbl.length t) init in
ignore
(Hashtbl.fold (fun k v i -> a.(i) <- (k, v); i + 1) t 0) ;
a
let to_array_1c t =
let r =
Hashtbl.fold (fun k v seed ->
match seed with
Some (a,i) -> a.(i) <- (k,v); Some (a,i+1)
| None -> let a = Array.make (Hashtbl.length t) (k,v)
in
Some (a,1))
t None
in
match r with
None -> Array.init 0 (fun _ -> raise Not_found)
| Some (a, _) -> a
let h n =
let m = n * 1000 in
let h = Hashtbl.create m in
for i = 0 to m - 1 do
Hashtbl.replace h (Random.int max_int) (Random.int max_int);
done;
h
let main () =
let n = try int_of_string Sys.argv.(1) with _ -> 1 in
let h = h n in
let res = throughputN ~repeat:5 1
[("to_array_1", to_array_1, h);
("to_array_1b", to_array_1b, h);
("to_array_1c", to_array_1c, h);
("to_array_2", to_array_2, h);
("to_array_3", to_array_3, h);
("to_array_4", to_array_4, h);
("to_array_5", to_array_5, h);
] in
tabulate res
let () = main ()