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(*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*)
(** Qset - Set with (signed) rational multiplicity for each element *)
open Import0
include Qset_intf
module Make (Elt : sig
type t [@@deriving compare, sexp_of]
end) =
struct
module M = Map.Make (Elt)
type elt = Elt.t
type t = Q.t M.t
let compare = M.compare Q.compare
let equal = M.equal Q.equal
let hash_fold_t hash_fold_elt s m =
let hash_fold_q s q = Hash.fold_int s (Hashtbl.hash q) in
M.fold m
~init:(Hash.fold_int s (M.length m))
~f:(fun ~key ~data state -> hash_fold_q (hash_fold_elt state key) data)
let sexp_of_t s =
let sexp_of_q q = Sexp.Atom (Q.to_string q) in
List.sexp_of_t
(Sexplib.Conv.sexp_of_pair Elt.sexp_of_t sexp_of_q)
(M.to_alist s)
let t_of_sexp elt_of_sexp sexp =
let q_of_sexp = function
| Sexp.Atom s -> Q.of_string s
| _ -> assert false
in
List.fold_left
~f:(fun m (key, data) -> M.add_exn m ~key ~data)
~init:M.empty
(List.t_of_sexp
(Sexplib.Conv.pair_of_sexp elt_of_sexp q_of_sexp)
sexp)
let pp sep pp_elt fs s = List.pp sep pp_elt fs (M.to_alist s)
let empty = M.empty
let if_nz q = if Q.equal Q.zero q then None else Some q
let add m x i =
M.change m x ~f:(function Some j -> if_nz Q.(i + j) | None -> if_nz i)
let remove m x = M.remove m x
let union m n =
M.merge m n ~f:(fun ~key:_ -> function
| `Both (i, j) -> if_nz Q.(i + j) | `Left i | `Right i -> Some i )
let map m ~f =
let m' = empty in
let m, m' =
M.fold m ~init:(m, m') ~f:(fun ~key:x ~data:i (m, m') ->
let x', i' = f x i in
if x' == x then
if Q.equal i' i then (m, m') else (M.set m ~key:x ~data:i', m')
else (M.remove m x, add m' x' i') )
in
M.fold m' ~init:m ~f:(fun ~key:x ~data:i m -> add m x i)
let map_counts m ~f = M.mapi ~f:(fun ~key ~data -> f key data) m
let length m = M.length m
let count m x = match M.find m x with Some q -> q | None -> Q.zero
let min_elt_exn = M.min_elt_exn
let min_elt = M.min_elt
let to_list m = M.to_alist m
let iter m ~f = M.iteri ~f:(fun ~key ~data -> f key data) m
let exists m ~f = M.existsi ~f:(fun ~key ~data -> f key data) m
let fold m ~f ~init = M.fold ~f:(fun ~key ~data -> f key data) m ~init
end