val graph : ?loops:bool -> v:int -> e:int -> unit -> tval labeled : (V.t -> V.t -> E.label) -> ?loops:bool -> v:int -> e:int -> unit -> tval gnp : ?loops:bool -> v:int -> prob:float -> unit -> tval gnp_labeled : (V.t -> V.t -> E.label) -> ?loops:bool -> v:int -> prob:float -> unit -> t