Game of Life Ocaml with Matrix - arrays

Question

I have generated a matrix for my Game of Life, and I'm trying to make it so that it loops through and continuously prints out the next generation, I am using a code I found online, and it doesn't seem to work. Here is my code
let generation = ref 1
let get g x y =
try g.(x).(y)
with _ -> 0
;;
let neighbourhood g x y =
(get g (x-1) (y-1)) +
(get g (x-1) (y )) +
(get g (x-1) (y+1)) +
(get g (x ) (y-1)) +
(get g (x ) (y+1)) +
(get g (x+1) (y-1)) +
(get g (x+1) (y )) +
(get g (x+1) (y+1))
let next_cell g x y =
let n = neighbourhood g x y in
match g.(x).(y), n with
| 1, 0 | 1, 1 -> 0 (* lonely *)
| 1, 4 | 1, 5 | 1, 6 | 1, 7 | 1, 8 -> 0 (* overcrowded *)
| 1, 2 | 1, 3 -> 1 (* lives *)
| 0, 3 -> 1 (* get birth *)
| _ -> 0
let copy g = Array.map Array.copy g
let rec next g =
let width = Array.length g
and height = Array.length g.(0)
and new_g = copy g in
for x = 0 to pred width do
for y = 0 to pred height do
new_g.(x).(y) <- (next_cell g x y)
done
done;
next new_g
let print g =
let width = Array.length g
and height = Array.length g.(0) in
for x = 0 to pred width do
for y = 0 to pred height do
if g.(x).(y) = 0
then print_char '.'
else print_char 'o'
done;
print_newline()
done
;;
print_string "Width ";
let num = read_int () in
print_string "Height";
let num2 = read_int () in
while !generation < 100 do
let myArray = Array.init num (fun _ -> Array.init num2 (fun _ -> Random.int 2)) in
print_string "Generation: "; print_int !generation; print_string "\n";
print (next myArray);
generation := !generation +1;
print_newline();
done;;
It only prints out the initial one and the generation after that rather than a new one. Since the parameters is the original array, however, when I put print (next new_g) it gives me an unbound value, is there a way I can continuously print out the subsequent generations?Shouldn't it overwrite the existing new_g when I do that?

Answer 1

Looking just at the main while loop, it allocates and initializes a random array each time around the loop. It doesn't seem like this could be right.
I also don't see how the function next could work, as it never returns. Its last action is to call itself again, unconditionally.
Update
If you change the last line of next to this:
new_g
it returns the next generation each time you call it.
Here's a way to drive the code in a functional (rather than imperative) style:
let rec generation n array =
if n < 100 then
begin
(* Print the array *);
generation (n + 1) (next array)
end
The outermost code might look like this:
let myArray =
Array.init num
(fun _ -> Array.init num2 (fun _ -> Random.int 2))
in
generation 0 myArray