# binary-trees OCaml #2 program

## source code

```(* The Computer Language Benchmarks Game
* https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
*
* Contributed by Troestler Christophe
* Rough parallelization by Mauricio Fernandez
* *reset*
*)

type 'a tree = Empty | Node of 'a tree * 'a tree

let rec make d =
(* if d = 0 then Empty *)
if d = 0 then Node(Empty, Empty)
else let d = d - 1 in Node(make d, make d)

let rec check = function Empty -> 0 | Node(l, r) -> 1 + check l + check r

let min_depth = 4
let max_depth = (let n = try int_of_string(Array.get Sys.argv 1) with _ -> 10 in
max (min_depth + 2) n)
let stretch_depth = max_depth + 1

let () =
(* Gc.set { (Gc.get()) with Gc.minor_heap_size = 1024 * 1024; max_overhead = -1; }; *)
let c = check (make stretch_depth) in
Printf.printf "stretch tree of depth %i\t check: %i\n" stretch_depth c

let long_lived_tree = make max_depth

let rec loop_depths d =
let worker d =
let niter = 1 lsl (max_depth - d + min_depth) and c = ref 0 in
for i = 1 to niter do c := !c + check(make d) done;
(niter, !c) in
let workers = Array.init ((max_depth - d) / 2 + 1)
(fun i -> let d = d + i * 2 in (d, invoke worker d))
in Array.iter
(fun (d, w) ->
let niter, c = w () in
Printf.printf "%i\t trees of depth %i\t check: %i\n" niter d c)
workers

(* function originally due to Jon D. Harrop *)
and invoke (f : 'a -> 'b) x : unit -> 'b =
let input, output = Unix.pipe() in
match Unix.fork() with
| -1 -> Unix.close input; Unix.close output; (let v = f x in fun () -> v)
| 0 ->
Unix.close input;
let output = Unix.out_channel_of_descr output in
Marshal.to_channel output (try `Res(f x) with e -> `Exn e) [];
close_out output;
exit 0
| pid ->
Unix.close output;
let input = Unix.in_channel_of_descr input in
fun () ->
let v = Marshal.from_channel input in
ignore (Unix.waitpid [] pid);
close_in input;
match v with
| `Res x -> x
| `Exn e -> raise e

let () =
flush stdout;
loop_depths min_depth;
Printf.printf "long lived tree of depth %i\t check: %i\n"
max_depth (check long_lived_tree)

```

## notes, command-line, and program output

```NOTES:
64-bit Ubuntu quad core
The OCaml native-code compiler, version 4.11.0

Fri, 23 Oct 2020 23:19:27 GMT

MAKE:
mv binarytrees.ocaml-2.ocaml binarytrees.ocaml-2.ml
~/.opam/4.11.0/bin/ocamlopt -noassert -unsafe -fPIC -nodynlink -inline 100 -O3 unix.cmxa -ccopt -march=ivybridge binarytrees.ocaml-2.ml -o binarytrees.ocaml-2.ocaml_run
rm binarytrees.ocaml-2.ml

1.23s to complete and log all make actions

COMMAND LINE:
./binarytrees.ocaml-2.ocaml_run 21

PROGRAM OUTPUT:
stretch tree of depth 22	 check: 8388607
2097152	 trees of depth 4	 check: 65011712
524288	 trees of depth 6	 check: 66584576
131072	 trees of depth 8	 check: 66977792
32768	 trees of depth 10	 check: 67076096
8192	 trees of depth 12	 check: 67100672
2048	 trees of depth 14	 check: 67106816
512	 trees of depth 16	 check: 67108352
128	 trees of depth 18	 check: 67108736
32	 trees of depth 20	 check: 67108832
long lived tree of depth 21	 check: 4194303
```