diff --git a/ocaml/Bitlist.ml b/ocaml/Bitlist.ml
index 02cc680f..c333485a 100644
--- a/ocaml/Bitlist.ml
+++ b/ocaml/Bitlist.ml
@@ -64,7 +64,7 @@ let of_int64_list l =
 
 (* Compute n_int *)
 let n_int_of_mo_tot_num mo_tot_num =
-  let bit_kind_size = Bit_kind_size.to_int Qpackage.bit_kind_size in
+  let bit_kind_size = Bit_kind_size.to_int (Lazy.force Qpackage.bit_kind_size) in
   N_int_number.of_int ( (mo_tot_num-1)/bit_kind_size + 1 )
 ;;
 
diff --git a/ocaml/Qpackage.ml b/ocaml/Qpackage.ml
index 603cbaa1..9726deb6 100644
--- a/ocaml/Qpackage.ml
+++ b/ocaml/Qpackage.ml
@@ -10,7 +10,7 @@ Please source the quantum_package.rc file."
   | Some x -> x 
 ;;
 
-let bit_kind_size = 
+let bit_kind_size = lazy (
   let filename = root^"/src/Bitmask/bitmasks_module.f90" in
   if not (Sys.file_exists_exn filename) then
      raise (Failure ("File "^filename^" not found"));
@@ -37,5 +37,5 @@ let bit_kind_size =
      | _ -> get_data tail
      end
   in
-  get_data lines
+  get_data lines )
 ;;