diff --git a/Basis/OneElectronRR.ml b/Basis/OneElectronRR.ml
index 2be685f..bac802c 100644
--- a/Basis/OneElectronRR.ml
+++ b/Basis/OneElectronRR.ml
@@ -110,10 +110,7 @@ let hvrr_one_e
             h1 +. f2 *. h2
 
   in
-  hrr
-    (angMom_a.(0),angMom_a.(1),angMom_a.(2))
-    (angMom_b.(0),angMom_b.(1),angMom_b.(2))
-    totAngMom_a totAngMom_b
+  hrr angMom_a angMom_b totAngMom_a totAngMom_b
 
 
 
@@ -200,9 +197,9 @@ let contracted_class_shell_pair ~zero_m shell_p geometry : float Zmap.t =
             class_indices
             |> Array.iteri (fun i key ->
                 let (angMomA,angMomB) =
-                  let a = Zkey.to_int_array Zkey.Kind_6 key in
-                  ( [| a.(0) ;  a.(1) ;  a.(2) |], 
-                    [| a.(3) ;  a.(4) ;  a.(5) |])
+                  match Zkey.to_int_tuple ~kind:Zkey.Kind_6 key with
+                  | Zkey.Six x -> x
+                  | _          -> assert false
                 in
                 let norm = norm_coef_scale.(i) in
                 let coef_prod = coef_prod *. norm in
diff --git a/Basis/TwoElectronRR.ml b/Basis/TwoElectronRR.ml
index bdadb85..af1448d 100644
--- a/Basis/TwoElectronRR.ml
+++ b/Basis/TwoElectronRR.ml
@@ -9,7 +9,7 @@ exception NullQuartet
 
 (** Horizontal and Vertical Recurrence Relations (HVRR) *)
 let hvrr_two_e (angMom_a, angMom_b, angMom_c, angMom_d)
-    (totAngMom_a, totAngMom_b, totAngMom_c, totAngMom_d)
+    (totAngMom_a_in, totAngMom_b_in, totAngMom_c_in, totAngMom_d_in)
     (maxm, zero_m_array)
     (expo_b, expo_d)
     (expo_inv_p, expo_inv_q)
@@ -18,20 +18,20 @@ let hvrr_two_e (angMom_a, angMom_b, angMom_c, angMom_d)
   =
 
   let maxsze = maxm+1 in
-  let totAngMom_a = Angular_momentum.to_int totAngMom_a
-  and totAngMom_b = Angular_momentum.to_int totAngMom_b
-  and totAngMom_c = Angular_momentum.to_int totAngMom_c
-  and totAngMom_d = Angular_momentum.to_int totAngMom_d
+  let totAngMom_a = Angular_momentum.to_int totAngMom_a_in
+  and totAngMom_b = Angular_momentum.to_int totAngMom_b_in
+  and totAngMom_c = Angular_momentum.to_int totAngMom_c_in
+  and totAngMom_d = Angular_momentum.to_int totAngMom_d_in
   in
   let maxm = totAngMom_a + totAngMom_b + totAngMom_c + totAngMom_d in
   let empty = Array.make (maxm+1) 0. 
   in
   if debug then begin
     Printf.printf "\n---- %d %d %d %d ----\n"  totAngMom_a totAngMom_b totAngMom_c totAngMom_d;
-    Printf.printf "%d %d %d\n"  angMom_a.(0)  angMom_a.(1)  angMom_a.(2) ;
-    Printf.printf "%d %d %d\n"  angMom_b.(0)  angMom_b.(1)  angMom_b.(2) ;
-    Printf.printf "%d %d %d\n"  angMom_c.(0)  angMom_c.(1)  angMom_c.(2) ;
-    Printf.printf "%d %d %d\n"  angMom_d.(0)  angMom_d.(1)  angMom_d.(2) ;
+    let (x,y,z) = angMom_a in Printf.printf "%d %d %d\n" x y z;
+    let (x,y,z) = angMom_b in Printf.printf "%d %d %d\n" x y z;
+    let (x,y,z) = angMom_c in Printf.printf "%d %d %d\n" x y z;
+    let (x,y,z) = angMom_d in Printf.printf "%d %d %d\n" x y z;
     Printf.printf "%f %f %f %f\n%f %f %f\n%f %f %f\n%f %f %f\n"  expo_b expo_d
       expo_inv_p expo_inv_q
       (Coordinate.coord center_ab 0) (Coordinate.coord center_ab 1) (Coordinate.coord center_ab 2)
@@ -100,7 +100,14 @@ let hvrr_two_e (angMom_a, angMom_b, angMom_c, angMom_d)
       end;
 
     match (totAngMom_a, totAngMom_c) with
-    | (i,0) -> if (i>0) then vrr0 angMom_a totAngMom_a else zero_m_array 
+    | (i,0) -> if (i>0) then
+    vrr0 angMom_a totAngMom_a
+    (*
+    OneElectronRR.hvrr_one_e (angMom_a, angMom_b) (totAngMom_a_in, totAngMom_b_in)
+      (maxm, zero_m_array) (expo_b) (expo_inv_p) (center_ab, center_pq, center_ab)
+                map_1d
+    *)
+      else zero_m_array 
     | (_,_) ->
       let key =  Zkey.of_int_tuple (Zkey.Six (angMom_a, angMom_c) ) in
 
@@ -284,11 +291,7 @@ let hvrr_two_e (angMom_a, angMom_b, angMom_c, angMom_d)
         h1 +. f2 *. h2
 
   in
-  hrr
-    (angMom_a.(0),angMom_a.(1),angMom_a.(2))
-    (angMom_b.(0),angMom_b.(1),angMom_b.(2))
-    (angMom_c.(0),angMom_c.(1),angMom_c.(2))
-    (angMom_d.(0),angMom_d.(1),angMom_d.(2))
+  hrr angMom_a angMom_b angMom_c angMom_d
     totAngMom_a totAngMom_b totAngMom_c totAngMom_d
 
 
@@ -376,12 +379,10 @@ let contracted_class_shell_pairs ~zero_m ?schwartz_p ?schwartz_q shell_p shell_q
             (* Compute the integral class from the primitive shell quartet *)
             class_indices
             |> Array.iteri (fun i key ->
-                let a = Zkey.to_int_array Zkey.Kind_12 key in
                 let (angMomA,angMomB,angMomC,angMomD) =
-                  ( [| a.(0) ;  a.(1) ;  a.(2) |], 
-                    [| a.(3) ;  a.(4) ;  a.(5) |], 
-                    [| a.(6) ;  a.(7) ;  a.(8) |], 
-                    [| a.(9) ; a.(10) ; a.(11) |] )
+                  match Zkey.to_int_tuple ~kind:Zkey.Kind_12 key with
+                  | Zkey.Twelve x -> x
+                  | _             -> assert false
                 in
                 try
                     (*