73 lines
2.5 KiB
OCaml
73 lines
2.5 KiB
OCaml
(** This module offers the abstract data type of a partition of
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classes of equivalent items (Union & Find). *)
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(** The items are of type [Item.t], that is, they have to obey
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a total order, but also they must be printable to ease
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debugging. The signature [Item] is the input signature of
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the functor {!Partition.Make}. *)
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module type Item =
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sig
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(** Type of items *)
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type t
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(** Same convention as {!Pervasives.compare} *)
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val compare : t -> t -> int
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val to_string : t -> string
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end
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(** The module signature [S] is the output signature of the functor
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{!Partition.Make}. *)
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module type S =
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sig
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type item
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type partition
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type t = partition
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(** {1 Creation} *)
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(** The value [empty] is an empty partition. *)
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val empty : partition
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(** The value of [equiv i j p] is the partition [p] extended with
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the equivalence of items [i] and [j]. If both [i] and [j] are
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already known to be equivalent, then [equiv i j p == p]. *)
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val equiv : item -> item -> partition -> partition
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(** The value of [alias i j p] is the partition [p] extended with
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the fact that item [i] is an alias of item [j]. This is the
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same as [equiv i j p], except that it is guaranteed that the
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item [i] is not the representative of its equivalence class in
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[alias i j p]. *)
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val alias : item -> item -> partition -> partition
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(** {1 Projection} *)
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(** The value of the call [repr i p] is [j] if the item [i] is in
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the partition [p] and its representative is [j]. If [i] is not
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in [p], then the value is [i]. *)
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val repr : item -> partition -> item
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(** The value of the call [mem i p] is [Some j] if the item [i] is
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in the partition [p] and its representative is [j]. If [i] is
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not in [p], then the value is [None]. *)
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val mem : item -> partition -> item option
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(** The call [print p] is a value of type [Buffer.t] containing
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strings denoting the partition [p], based on
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[Ord.to_string]. *)
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val print : partition -> Buffer.t
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(** {1 Predicates} *)
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(** The value of [is_equiv i j p] is [true] if, and only if, the
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items [i] and [j] belong to the same equivalence class in the
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partition [p], that is, [i] and [j] have the same
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representative. In particular, if either [i] or [j] do not
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belong to [p], the value of [is_equiv i j p] is [false]. See
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[mem] above. *)
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val is_equiv : item -> item -> partition -> bool
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end
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module Make (Ord : Item) : S with type item = Ord.t
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