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 *)
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 ()