+
+module N6 =
+struct
+ type 'a t = 'a N3.t N3.t
+
+ let create _n a =
+ let dummy1 = N3.create 512 a in
+ N3.create 512 dummy1
+
+ let add a i j k l m n v =
+ let line = N3.find a i j k in
+ if line == N3.dummy a then
+ let nline = N3.create 0 (N3.dummy line) in
+ N3.add a i j k nline;
+ N3.add nline l m n v
+ else
+ N3.add line l m n v
+
+ let find a i j k l m n =
+ let v = N3.find a i j k in
+ if v == N3.dummy a then N3.dummy (N3.dummy a)
+ else N3.find v l m n
+
+
+ let dummy a = N3.dummy (N3.dummy a)
+ let iteri _f _a = assert false
+end