open Bigarray

let transpose b =
  let dim1 = Array2.dim1 b
  and dim2 = Array2.dim2 b in
  let kind = Array2.kind b
  and layout = Array2.layout b in
  let b' = Array2.create kind layout dim2 dim1 in
  for i=0 to pred dim1 do
    for j=0 to pred dim2 do
      b'.{j,i} <- b.{i,j}
    done;
  done;
  (b')
;;

let array2_display print newline b =
  for i=0 to Array2.dim1 b - 1 do
    for j=0 to Array2.dim2 b - 1 do
      print b.{i,j}
    done;
    newline();
  done;
;;

let a = Array2.of_array int c_layout [|
  [| 1; 2; 3; 4 |];
  [| 5; 6; 7; 8 |];
|]
;;

array2_display (Printf.printf " %d") print_newline (transpose a) ;;