diff --git a/ocaml/Input.ml b/ocaml/Input.ml
index a861e3ec..9d5f6b7f 100644
--- a/ocaml/Input.ml
+++ b/ocaml/Input.ml
@@ -11,5 +11,6 @@ include Input_cisd_sc2;;
 include Input_determinants;;
 include Input_electrons;;
 include Input_full_ci;;
+include Input_hartree_fock;;
 
 
diff --git a/ocaml/Input_ao_basis.ml b/ocaml/Input_ao_basis.ml
index 8bf2a303..276e4b8d 100644
--- a/ocaml/Input_ao_basis.ml
+++ b/ocaml/Input_ao_basis.ml
@@ -6,12 +6,12 @@ module Ao_basis : sig
   type t = 
     { ao_basis        : string ;
       ao_num          : AO_number.t ;
-      ao_prim_num     : Strictly_positive_int.t array;
-      ao_prim_num_max : Strictly_positive_int.t;
+      ao_prim_num     : AO_prim_number.t array;
+      ao_prim_num_max : AO_prim_number.t;
       ao_nucl         : Nucl_number.t array;
       ao_power        : Symmetry.Xyz.t array;
-      ao_coef         : float array;
-      ao_expo         : Positive_float.t array;
+      ao_coef         : AO_coef.t array;
+      ao_expo         : AO_expo.t array;
     }
   ;;
   val read : unit -> t
@@ -20,12 +20,12 @@ end = struct
   type t = 
     { ao_basis        : string ;
       ao_num          : AO_number.t ;
-      ao_prim_num     : Strictly_positive_int.t array;
-      ao_prim_num_max : Strictly_positive_int.t;
+      ao_prim_num     : AO_prim_number.t array;
+      ao_prim_num_max : AO_prim_number.t;
       ao_nucl         : Nucl_number.t array;
       ao_power        : Symmetry.Xyz.t array;
-      ao_coef         : float array;
-      ao_expo         : Positive_float.t array;
+      ao_coef         : AO_coef.t array;
+      ao_expo         : AO_expo.t array;
     }
   ;;
 
@@ -46,14 +46,14 @@ end = struct
   let read_ao_prim_num () =
     (Ezfio.get_ao_basis_ao_prim_num () ).Ezfio.data
     |> Ezfio.flattened_ezfio_data
-    |> Array.map ~f:Strictly_positive_int.of_int
+    |> Array.map ~f:AO_prim_number.of_int
   ;;
 
   let read_ao_prim_num_max () =
     (Ezfio.get_ao_basis_ao_prim_num () ).Ezfio.data
     |> Ezfio.flattened_ezfio_data
     |> Array.fold ~f:(fun x y -> if x>y then x else y) ~init:0
-    |> Strictly_positive_int.of_int
+    |> AO_prim_number.of_int
   ;;
 
   let read_ao_nucl () =
@@ -82,12 +82,13 @@ end = struct
   let read_ao_coef () =
     (Ezfio.get_ao_basis_ao_coef () ).Ezfio.data
     |> Ezfio.flattened_ezfio_data
+    |> Array.map ~f:AO_coef.of_float
   ;;
 
   let read_ao_expo () =
     (Ezfio.get_ao_basis_ao_expo () ).Ezfio.data
     |> Ezfio.flattened_ezfio_data
-    |> Array.map ~f:Positive_float.of_float
+    |> Array.map ~f:AO_expo.of_float
   ;;
 
   let read () =
@@ -116,15 +117,15 @@ ao_expo         = %s
     b.ao_basis
     (AO_number.to_string b.ao_num)
     (b.ao_prim_num |> Array.to_list |> List.map
-      ~f:(Strictly_positive_int.to_string) |> String.concat ~sep:", " )
-    (Strictly_positive_int.to_string b.ao_prim_num_max)
+      ~f:(AO_prim_number.to_string) |> String.concat ~sep:", " )
+    (AO_prim_number.to_string b.ao_prim_num_max)
     (b.ao_nucl |> Array.to_list |> List.map ~f:Nucl_number.to_string |>
       String.concat ~sep:", ")
     (b.ao_power |> Array.to_list |> List.map ~f:(fun x->
       "("^(Symmetry.Xyz.to_string x)^")" )|> String.concat ~sep:", ")
-    (b.ao_coef  |> Array.to_list |> List.map ~f:Float.to_string
+    (b.ao_coef  |> Array.to_list |> List.map ~f:AO_coef.to_string
       |> String.concat ~sep:", ")
-    (b.ao_expo  |> Array.to_list |> List.map ~f:Positive_float.to_string
+    (b.ao_expo  |> Array.to_list |> List.map ~f:AO_expo.to_string
       |> String.concat ~sep:", ")
 
 end
diff --git a/ocaml/Input_bi_integrals.ml b/ocaml/Input_bi_integrals.ml
index e040ce5f..3322f4c2 100644
--- a/ocaml/Input_bi_integrals.ml
+++ b/ocaml/Input_bi_integrals.ml
@@ -8,8 +8,8 @@ module Bielec_integrals : sig
       read_mo_integrals  : bool;
       write_ao_integrals : bool;
       write_mo_integrals : bool;
-      threshold_ao       : Positive_float.t;
-      threshold_mo       : Positive_float.t;
+      threshold_ao       : Threshold.t;
+      threshold_mo       : Threshold.t;
       direct             : bool;
     }
   ;;
@@ -21,8 +21,8 @@ end = struct
       read_mo_integrals  : bool;
       write_ao_integrals : bool;
       write_mo_integrals : bool;
-      threshold_ao       : Positive_float.t;
-      threshold_mo       : Positive_float.t;
+      threshold_ao       : Threshold.t;
+      threshold_mo       : Threshold.t;
       direct             : bool;
     }
   ;;
@@ -81,7 +81,7 @@ end = struct
        |> Ezfio.set_bielec_integrals_threshold_ao
     ;
     Ezfio.get_bielec_integrals_threshold_ao ()
-    |> Positive_float.of_float
+    |> Threshold.of_float
   ;;
 
   let read_threshold_mo () = 
@@ -91,7 +91,7 @@ end = struct
        |> Ezfio.set_bielec_integrals_threshold_mo
     ;
     Ezfio.get_bielec_integrals_threshold_mo ()
-    |> Positive_float.of_float
+    |> Threshold.of_float
   ;;
 
   let read ()= 
@@ -127,8 +127,8 @@ direct             = %s
         (Bool.to_string b.read_mo_integrals)
         (Bool.to_string b.write_ao_integrals)
         (Bool.to_string b.write_mo_integrals)
-        (Positive_float.to_string b.threshold_ao)
-        (Positive_float.to_string b.threshold_mo)
+        (Threshold.to_string b.threshold_ao)
+        (Threshold.to_string b.threshold_mo)
         (Bool.to_string b.direct)
 end
 
diff --git a/ocaml/Input_bitmasks.ml b/ocaml/Input_bitmasks.ml
index 9e60b67e..be82f603 100644
--- a/ocaml/Input_bitmasks.ml
+++ b/ocaml/Input_bitmasks.ml
@@ -6,7 +6,7 @@ module Bitmasks : sig
   type t = 
     { n_int              : N_int_number.t;
       bit_kind           : Bit_kind.t;
-      n_mask_gen         : Strictly_positive_int.t;
+      n_mask_gen         : Bitmask_number.t;
       generators         : int64 array;
     }
   ;;
@@ -16,7 +16,7 @@ end = struct
   type t = 
     { n_int              : N_int_number.t;
       bit_kind           : Bit_kind.t;
-      n_mask_gen         : Strictly_positive_int.t;
+      n_mask_gen         : Bitmask_number.t;
       generators         : int64 array;
     }
   ;;
@@ -49,7 +49,7 @@ end = struct
       Ezfio.set_bitmasks_n_mask_gen 1
     ;
     Ezfio.get_bitmasks_n_mask_gen ()
-    |> Strictly_positive_int.of_int
+    |> Bitmask_number.of_int
   ;;
 
 
@@ -93,7 +93,7 @@ generators         = %s
 "
         (N_int_number.to_string b.n_int)
         (Bit_kind.to_string b.bit_kind)
-        (Strictly_positive_int.to_string b.n_mask_gen)
+        (Bitmask_number.to_string b.n_mask_gen)
         (Array.to_list b.generators
          |> List.map ~f:(fun x-> Int64.to_string x) 
          |> String.concat ~sep:", ")
diff --git a/ocaml/Input_cis.ml b/ocaml/Input_cis.ml
index 3ee0e93b..6b521872 100644
--- a/ocaml/Input_cis.ml
+++ b/ocaml/Input_cis.ml
@@ -4,7 +4,7 @@ open Core.Std;;
 
 module Cis_dressed : sig
   type t = 
-    { n_state_cis        : Strictly_positive_int.t;
+    { n_state_cis        : States_number.t;
       n_core_cis         : Positive_int.t;
       n_act_cis          : Positive_int.t;
       mp2_dressing       : bool;
@@ -16,7 +16,7 @@ module Cis_dressed : sig
   val to_string : t -> string
 end = struct
   type t = 
-    { n_state_cis        : Strictly_positive_int.t;
+    { n_state_cis        : States_number.t;
       n_core_cis         : Positive_int.t;
       n_act_cis          : Positive_int.t;
       mp2_dressing       : bool;
@@ -34,7 +34,7 @@ end = struct
        |> Ezfio.set_cis_dressed_n_state_cis
     ;
     Ezfio.get_cis_dressed_n_state_cis ()
-    |> Strictly_positive_int.of_int
+    |> States_number.of_int
   ;;
 
   let read_n_core_cis () = 
@@ -102,7 +102,7 @@ mp2_dressing       = %s
 standard_doubles   = %s
 en_2_2             = %s
 "
-        (Strictly_positive_int.to_string b.n_state_cis)
+        (States_number.to_string b.n_state_cis)
         (Positive_int.to_string b.n_core_cis)
         (Positive_int.to_string b.n_act_cis)
         (Bool.to_string b.mp2_dressing)
diff --git a/ocaml/Input_cisd_sc2.ml b/ocaml/Input_cisd_sc2.ml
index a976e683..4a5461f4 100644
--- a/ocaml/Input_cisd_sc2.ml
+++ b/ocaml/Input_cisd_sc2.ml
@@ -4,8 +4,8 @@ open Core.Std;;
 
 module Cisd_sc2 : sig
   type t = 
-    { n_det_max_cisd_sc2 : Strictly_positive_int.t;
-      pt2_max            : Positive_float.t;
+    { n_det_max_cisd_sc2 : Det_number.t;
+      pt2_max            : PT2_energy.t;
       do_pt2_end         : bool;
     }
   ;;
@@ -13,8 +13,8 @@ module Cisd_sc2 : sig
   val to_string : t -> string
 end = struct
   type t = 
-    { n_det_max_cisd_sc2 : Strictly_positive_int.t;
-      pt2_max            : Positive_float.t;
+    { n_det_max_cisd_sc2 : Det_number.t;
+      pt2_max            : PT2_energy.t;
       do_pt2_end         : bool;
     }
   ;;
@@ -28,7 +28,7 @@ end = struct
        |> Ezfio.set_cisd_sc2_selected_n_det_max_cisd_sc2 
     ;
     Ezfio.get_cisd_sc2_selected_n_det_max_cisd_sc2 ()
-    |> Strictly_positive_int.of_int
+    |> Det_number.of_int
   ;;
 
 
@@ -39,7 +39,7 @@ end = struct
        |> Ezfio.set_cisd_sc2_selected_pt2_max
     ;
     Ezfio.get_cisd_sc2_selected_pt2_max ()
-    |> Positive_float.of_float
+    |> PT2_energy.of_float
   ;;
 
 
@@ -66,8 +66,8 @@ n_det_max_cisd_sc2 = %s
 pt2_max            = %s
 do_pt2_end         = %s
 "
-        (Strictly_positive_int.to_string b.n_det_max_cisd_sc2)
-        (Positive_float.to_string b.pt2_max)
+        (Det_number.to_string b.n_det_max_cisd_sc2)
+        (PT2_energy.to_string b.pt2_max)
         (Bool.to_string b.do_pt2_end)
 end
 
diff --git a/ocaml/Input_determinants.ml b/ocaml/Input_determinants.ml
index 7a2e1ddf..fb2f599f 100644
--- a/ocaml/Input_determinants.ml
+++ b/ocaml/Input_determinants.ml
@@ -11,8 +11,8 @@ module Determinants : sig
       n_states               : States_number.t;
       n_states_diag          : States_number.t;
       n_det_max_jacobi       : Det_number.t;
-      threshold_generators   : Positive_float.t;
-      threshold_selectors    : Positive_float.t; 
+      threshold_generators   : Threshold.t;
+      threshold_selectors    : Threshold.t; 
       read_wf                : bool;
       expected_s2            : Positive_float.t;
       s2_eig                 : bool;
@@ -31,8 +31,8 @@ end = struct
       n_states               : States_number.t;
       n_states_diag          : States_number.t;
       n_det_max_jacobi       : Det_number.t;
-      threshold_generators   : Positive_float.t;
-      threshold_selectors    : Positive_float.t; 
+      threshold_generators   : Threshold.t;
+      threshold_selectors    : Threshold.t; 
       read_wf                : bool;
       expected_s2            : Positive_float.t;
       s2_eig                 : bool;
@@ -116,7 +116,7 @@ end = struct
       |> Ezfio.set_determinants_threshold_generators
     ;
     Ezfio.get_determinants_threshold_generators ()
-    |> Positive_float.of_float
+    |> Threshold.of_float
   ;;
 
   let read_threshold_selectors () =
@@ -126,7 +126,7 @@ end = struct
       |> Ezfio.set_determinants_threshold_selectors
     ;
     Ezfio.get_determinants_threshold_selectors ()
-    |> Positive_float.of_float
+    |> Threshold.of_float
   ;;
 
   let read_read_wf () =
@@ -257,8 +257,8 @@ psi_det                = %s
      (b.n_states      |> States_number.to_string)
      (b.n_states_diag |> States_number.to_string)
      (b.n_det_max_jacobi |> Det_number.to_string)
-     (b.threshold_generators |> Positive_float.to_string)
-     (b.threshold_selectors |> Positive_float.to_string)
+     (b.threshold_generators |> Threshold.to_string)
+     (b.threshold_selectors |> Threshold.to_string)
      (b.read_wf       |> Bool.to_string)
      (b.expected_s2   |> Positive_float.to_string)
      (b.s2_eig        |> Bool.to_string)
@@ -266,7 +266,6 @@ psi_det                = %s
       |> String.concat ~sep:", ")
      (b.psi_det   |> Array.map ~f:(fun x -> Determinant.to_int64_array x
       |> Array.map ~f:(fun x-> 
-          print_endline (Int64.to_string x) ;
           Int64.to_string x )|> Array.to_list |>
        String.concat ~sep:", ") |> Array.to_list
       |> String.concat ~sep:" | ")
diff --git a/ocaml/Input_electrons.ml b/ocaml/Input_electrons.ml
index af016d08..75785aea 100644
--- a/ocaml/Input_electrons.ml
+++ b/ocaml/Input_electrons.ml
@@ -4,18 +4,18 @@ open Core.Std;;
 
 module Electrons : sig
   type t = 
-    { elec_alpha_num     : Strictly_positive_int.t;
-      elec_beta_num      : Positive_int.t;
-      elec_num           : Strictly_positive_int.t;
+    { elec_alpha_num     : Elec_alpha_number.t;
+      elec_beta_num      : Elec_beta_number.t;
+      elec_num           : Elec_number.t;
     }
   ;;
   val read : unit -> t
   val to_string : t -> string
 end = struct
   type t = 
-    { elec_alpha_num     : Strictly_positive_int.t;
-      elec_beta_num      : Positive_int.t;
-      elec_num           : Strictly_positive_int.t;
+    { elec_alpha_num     : Elec_alpha_number.t;
+      elec_beta_num      : Elec_beta_number.t;
+      elec_num           : Elec_number.t;
     }
   ;;
 
@@ -23,19 +23,19 @@ end = struct
 
   let read_elec_alpha_num() = 
     Ezfio.get_electrons_elec_alpha_num ()
-    |> Strictly_positive_int.of_int
+    |> Elec_alpha_number.of_int
   ;;
 
   let read_elec_beta_num() = 
     Ezfio.get_electrons_elec_beta_num ()
-    |> Positive_int.of_int
+    |> Elec_beta_number.of_int
   ;;
 
   let read_elec_num () = 
     let na = Ezfio.get_electrons_elec_alpha_num ()
     and nb = Ezfio.get_electrons_elec_beta_num  ()
     in assert (na >= nb);
-    Strictly_positive_int.of_int (na + nb)
+    Elec_number.of_int (na + nb)
   ;;
 
 
@@ -52,9 +52,9 @@ elec_alpha_num     = %s
 elec_beta_num      = %s
 elec_num           = %s
 "
-        (Strictly_positive_int.to_string b.elec_alpha_num)
-        (Positive_int.to_string b.elec_beta_num)
-        (Strictly_positive_int.to_string b.elec_num)
+        (Elec_alpha_number.to_string b.elec_alpha_num)
+        (Elec_beta_number.to_string b.elec_beta_num)
+        (Elec_number.to_string b.elec_num)
 end
 
 
diff --git a/ocaml/Input_full_ci.ml b/ocaml/Input_full_ci.ml
index 64de6498..bcff6681 100644
--- a/ocaml/Input_full_ci.ml
+++ b/ocaml/Input_full_ci.ml
@@ -4,8 +4,8 @@ open Core.Std;;
 
 module Full_ci : sig
   type t = 
-    { n_det_max_fci      : Strictly_positive_int.t;
-      pt2_max            : Positive_float.t;
+    { n_det_max_fci      : Det_number.t;
+      pt2_max            : PT2_energy.t;
       do_pt2_end         : bool;
     }
   ;;
@@ -13,8 +13,8 @@ module Full_ci : sig
   val to_string : t -> string
 end = struct
   type t = 
-    { n_det_max_fci      : Strictly_positive_int.t;
-      pt2_max            : Positive_float.t;
+    { n_det_max_fci      : Det_number.t;
+      pt2_max            : PT2_energy.t;
       do_pt2_end         : bool;
     }
   ;;
@@ -28,7 +28,7 @@ end = struct
        |> Ezfio.set_full_ci_n_det_max_fci
     ;
     Ezfio.get_full_ci_n_det_max_fci ()
-    |> Strictly_positive_int.of_int
+    |> Det_number.of_int
   ;;
 
   let read_pt2_max () = 
@@ -38,7 +38,7 @@ end = struct
        |> Ezfio.set_full_ci_pt2_max
     ;
     Ezfio.get_full_ci_pt2_max ()
-    |> Positive_float.of_float
+    |> PT2_energy.of_float
   ;;
 
   let read_do_pt2_end () = 
@@ -64,8 +64,8 @@ n_det_max_fci      = %s
 pt2_max            = %s
 do_pt2_end         = %s
 "
-        (Strictly_positive_int.to_string b.n_det_max_fci)
-        (Positive_float.to_string b.pt2_max)
+        (Det_number.to_string b.n_det_max_fci)
+        (PT2_energy.to_string b.pt2_max)
         (Bool.to_string b.do_pt2_end)
 end
 
diff --git a/ocaml/Input_hartree_fock.ml b/ocaml/Input_hartree_fock.ml
new file mode 100644
index 00000000..a612ae74
--- /dev/null
+++ b/ocaml/Input_hartree_fock.ml
@@ -0,0 +1,57 @@
+open Qptypes;;
+open Qputils;;
+open Core.Std;;
+
+module Hartree_fock : sig
+  type t = 
+    { n_it_scf_max       : Strictly_positive_int.t;
+      thresh_scf         : Threshold.t;
+    }
+  ;;
+  val read : unit -> t
+  val to_string : t -> string
+end = struct
+  type t = 
+    { n_it_scf_max       : Strictly_positive_int.t;
+      thresh_scf         : Threshold.t;
+    }
+  ;;
+
+  let get_default = Qpackage.get_ezfio_default "hartree_fock";;
+
+  let read_n_it_scf_max () = 
+    if not (Ezfio.has_hartree_fock_n_it_scf_max ()) then
+       get_default "n_it_scf_max"
+       |> Int.of_string
+       |> Ezfio.set_hartree_fock_n_it_scf_max
+    ;
+    Ezfio.get_hartree_fock_n_it_scf_max ()
+    |> Strictly_positive_int.of_int
+  ;;
+
+  let read_thresh_scf() = 
+    if not (Ezfio.has_hartree_fock_thresh_scf()) then
+       get_default "thresh_scf"
+       |> Float.of_string
+       |> Ezfio.set_hartree_fock_thresh_scf
+    ;
+    Ezfio.get_hartree_fock_thresh_scf ()
+    |> Threshold.of_float ;;
+
+
+  let read () = 
+    { n_it_scf_max       = read_n_it_scf_max ();
+      thresh_scf         = read_thresh_scf ();
+    }
+  ;;
+
+  let to_string b =
+    Printf.sprintf "
+n_it_scf_max       = %s
+thresh_scf         = %s
+"
+        (Strictly_positive_int.to_string b.n_it_scf_max)
+        (Threshold.to_string b.thresh_scf)
+end
+
+
diff --git a/ocaml/qptypes_generator.ml b/ocaml/qptypes_generator.ml
index 24b08b25..8ab5b5cf 100644
--- a/ocaml/qptypes_generator.ml
+++ b/ocaml/qptypes_generator.ml
@@ -99,10 +99,35 @@ let input_data = "
   | _ -> raise (Failure \"Bit_kind should be (1|2|4|8).\")
   end;
 
+* Bitmask_number : int
+  assert (x > 0) ;
+
 * MO_coef : float
 
 * AO_coef : float
 
+* AO_expo : float  
+  assert (x >= 0.) ; 
+
+* AO_prim_number : int
+  assert (x > 0) ;
+
+* Threshold : float
+  assert (x >= 0.) ;
+  assert (x <= 1.) ;
+
+* PT2_energy : float
+  assert (x >=0.) ;
+
+* Elec_alpha_number : int
+  assert (x > 0) ;
+
+* Elec_beta_number : int
+  assert (x >= 0) ;
+
+* Elec_number : int
+  assert (x > 0) ;
+
 "
 ;;
 
diff --git a/ocaml/test_input.ml b/ocaml/test_input.ml
index 4b7d135e..b88cd37c 100644
--- a/ocaml/test_input.ml
+++ b/ocaml/test_input.ml
@@ -54,4 +54,19 @@ let test_fci () =
   print_endline (Input.Full_ci.to_string b);
 ;;
 
-test_fci();;
+let test_hf () =
+  Ezfio.set_file "F2.ezfio" ;
+  let b = Input.Hartree_fock.read ()
+  in
+  print_endline (Input.Hartree_fock.to_string b);
+;;
+
+(*
+test_hf ();;
+test_ao ();;
+test_bielec_intergals ();;
+test_bitmasks ();
+test_cis ();
+test_dets ();
+*)
+test_cisd_sc2 ();