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https://github.com/c-cube/ocaml-containers.git
synced 2025-12-06 03:05:28 -05:00
comprehensive BFS;
implemented LazyGraph.Dot.pp (and pp_enum to have more control); LazyGraph.map and filter implemented too
This commit is contained in:
Simon Cruanes
parent
64a50fbedf
commit
1445104e2b
2 changed files with 138 additions and 52 deletions
186
lazyGraph.ml
186
lazyGraph.ml
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@ -149,6 +149,10 @@ module type S = sig
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| `Other of string * string
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] (** Dot attribute *)
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val pp_enum : name:string -> Format.formatter ->
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(attribute list,attribute list) Full.traverse_event Enum.t ->
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unit
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val pp : name:string -> (attribute list, attribute list) t ->
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Format.formatter ->
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vertex Enum.t -> unit
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@ -192,7 +196,6 @@ module Make(X : HASHABLE) : S with type vertex = X.t = struct
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(** A single node of the graph, with outgoing edges *)
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and 'e path = (vertex * 'e * vertex) list
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(** {2 Basic constructors} *)
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let empty =
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@ -223,73 +226,48 @@ module Make(X : HASHABLE) : S with type vertex = X.t = struct
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| EdgeBackward (* toward the current trail *)
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| EdgeTransverse (* toward a totally explored part of the graph *)
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let bfs_full ?(id=ref 0) ?(explored=H.create 5) graph vertices =
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let enum () =
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let q = Queue.create () in (* queue of nodes to explore *)
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Enum.iter (fun v -> Queue.push (v,[]) q) vertices;
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let rec next () =
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if Queue.is_empty q then raise Enum.EOG else
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let v', path = Queue.pop q in
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if H.mem explored v' then next ()
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else match graph v' with
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| Empty -> next ()
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| Node (_, label, edges) ->
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begin
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H.add explored v' ();
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(* explore neighbors *)
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Enum.iter
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(fun (e,v'') ->
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let path' = (v'',e,v') :: path in
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Queue.push (v'',path') q)
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edges;
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(* return this vertex *)
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let i = !id in
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incr id;
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Enum.of_list [EnterVertex (v', label, i, path); ExitVertex v']
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end
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in next
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in Enum.flatten enum
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(* helper type *)
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type 'e todo_item =
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| DFSEnter of vertex * 'e path
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| DFSExit of vertex
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| DFSFollowEdge of 'e path
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| FullEnter of vertex * 'e path
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| FullExit of vertex
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| FullFollowEdge of 'e path
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(** Is [v] part of the [path]? *)
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let rec mem_path path v =
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match path with
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| (v',_,v'')::path' ->
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(X.equal v v') || (X.equal v v'') || (mem_path path' v)
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| [] -> false
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let dfs_full ?(id=ref 0) ?(explored=H.create 5) graph vertices =
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let bfs_full ?(id=ref 0) ?(explored=H.create 5) graph vertices =
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fun () ->
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let s = Stack.create () in (* stack of nodes to explore *)
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Enum.iter (fun v -> Stack.push (DFSEnter (v,[])) s) vertices;
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let q = Queue.create () in (* queue of nodes to explore *)
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Enum.iter (fun v -> Queue.push (FullEnter (v,[])) q) vertices;
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let rec next () =
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if Stack.is_empty s then raise Enum.EOG else
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match Stack.pop s with
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| DFSExit v' -> ExitVertex v'
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| DFSEnter (v', path) ->
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if Queue.is_empty q then raise Enum.EOG else
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match Queue.pop q with
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| FullEnter (v', path) ->
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if H.mem explored v' then next ()
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(* explore the node now *)
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else begin match graph v' with
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| Empty -> next ()
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| Node (_, label, edges) ->
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H.add explored v' ();
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(* prepare to exit later *)
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Stack.push (DFSExit v') s;
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(* explore neighbors *)
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Enum.iter
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(fun (e,v'') ->
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Stack.push (DFSFollowEdge ((v'', e, v') :: path)) s)
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let path' = (v'',e,v') :: path in
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Queue.push (FullFollowEdge path') q)
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edges;
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(* exit node afterward *)
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Queue.push (FullExit v') q;
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(* return this vertex *)
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let i = !id in
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incr id;
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EnterVertex (v', label, i, path)
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end
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| DFSFollowEdge [] -> assert false
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| DFSFollowEdge (((v'', e, v') :: path) as path') ->
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| FullExit v' -> ExitVertex v'
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| FullFollowEdge [] -> assert false
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| FullFollowEdge (((v'', e, v') :: path) as path') ->
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(* edge path .... v' --e--> v'' *)
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if H.mem explored v''
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then if mem_path path v''
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@ -297,7 +275,48 @@ module Make(X : HASHABLE) : S with type vertex = X.t = struct
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else MeetEdge (v'', e, v', EdgeTransverse)
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else begin
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(* explore this edge *)
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Stack.push (DFSEnter (v'', path')) s;
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Queue.push (FullEnter (v'', path')) q;
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MeetEdge (v'', e, v', EdgeForward)
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end
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in next
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let dfs_full ?(id=ref 0) ?(explored=H.create 5) graph vertices =
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fun () ->
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let s = Stack.create () in (* stack of nodes to explore *)
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Enum.iter (fun v -> Stack.push (FullEnter (v,[])) s) vertices;
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let rec next () =
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if Stack.is_empty s then raise Enum.EOG else
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match Stack.pop s with
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| FullExit v' -> ExitVertex v'
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| FullEnter (v', path) ->
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if H.mem explored v' then next ()
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(* explore the node now *)
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else begin match graph v' with
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| Empty -> next ()
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| Node (_, label, edges) ->
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H.add explored v' ();
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(* prepare to exit later *)
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Stack.push (FullExit v') s;
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(* explore neighbors *)
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Enum.iter
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(fun (e,v'') ->
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Stack.push (FullFollowEdge ((v'', e, v') :: path)) s)
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edges;
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(* return this vertex *)
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let i = !id in
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incr id;
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EnterVertex (v', label, i, path)
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end
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| FullFollowEdge [] -> assert false
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| FullFollowEdge (((v'', e, v') :: path) as path') ->
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(* edge path .... v' --e--> v'' *)
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if H.mem explored v''
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then if mem_path path v''
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then MeetEdge (v'', e, v', EdgeBackward)
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else MeetEdge (v'', e, v', EdgeTransverse)
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else begin
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(* explore this edge *)
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Stack.push (FullEnter (v'', path')) s;
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MeetEdge (v'', e, v', EdgeForward)
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end
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in next
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@ -319,11 +338,13 @@ module Make(X : HASHABLE) : S with type vertex = X.t = struct
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let enum graph v = (Enum.empty, Enum.empty) (* TODO *)
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let depth graph v = failwith "not implemented"
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let depth graph v =
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failwith "not implemented" (* TODO *)
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(** Minimal path from the given Graph from the first vertex to
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the second. It returns both the distance and the path *)
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let min_path ?(distance=fun v1 e v2 -> 1) graph v1 v2 = failwith "not implemented"
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let min_path ?(distance=fun v1 e v2 -> 1) graph v1 v2 =
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failwith "not implemented"
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(** {2 Lazy transformations} *)
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@ -336,13 +357,28 @@ module Make(X : HASHABLE) : S with type vertex = X.t = struct
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| Node (_, l1, e1), Node (_, l2, e2) ->
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Node (v, combine l1 l2, Enum.append e1 e2)
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let map ~vertices ~edges g = failwith "not implemented"
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let map ~vertices ~edges g =
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fun vertex ->
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match g vertex with
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| Empty -> Empty
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| Node (_, l, edges_enum) ->
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let edges_enum' = Enum.map (fun (e,v') -> (edges e), v') edges_enum in
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Node (vertex, vertices l, edges_enum')
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let filter ?(vertices=fun v l -> true) ?(edges=fun v1 e v2 -> true) g =
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let filter ?(vertices=(fun v l -> true)) ?(edges=fun v1 e v2 -> true) g =
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fun vertex ->
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match g vertex with
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| Empty -> Empty
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| Node (_, l, edges_enum) when vertices vertex l ->
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(* filter out edges *)
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let edges_enum' = Enum.filter (fun (e,v') -> edges vertex e v') edges_enum in
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Node (vertex, l, edges_enum')
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| Node _ -> Empty (* filter out this vertex *)
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let limit_depth ~max g =
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(* TODO; this should be eager (compute depth by BFS) *)
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failwith "not implemented"
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let limit_depth ~max g = failwith "not implemented"
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module Infix = struct
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let (++) g1 g2 = union ?combine:None g1 g2
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end
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@ -357,8 +393,54 @@ module Make(X : HASHABLE) : S with type vertex = X.t = struct
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| `Other of string * string
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] (** Dot attribute *)
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(** Print an enum of Full.traverse_event *)
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let pp_enum ~name formatter events =
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(* print an attribute *)
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let print_attribute formatter attr =
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match attr with
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| `Color c -> Format.fprintf formatter "color=%s" c
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| `Shape s -> Format.fprintf formatter "shape=%s" s
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| `Weight w -> Format.fprintf formatter "weight=%d" w
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| `Style s -> Format.fprintf formatter "style=%s" s
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| `Label l -> Format.fprintf formatter "label=\"%s\"" l
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| `Other (name, value) -> Format.fprintf formatter "%s=\"%s\"" name value
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(* map from vertices to integers *)
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and get_id =
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let count = ref 0 in
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let m = H.create 5 in
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fun vertex ->
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try H.find m vertex
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with Not_found ->
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let n = !count in
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incr count;
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H.replace m vertex n;
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n
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in
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(* the unique name of a vertex *)
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let pp_vertex formatter v =
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Format.fprintf formatter "vertex_%d" (get_id v) in
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(* print preamble *)
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Format.fprintf formatter "@[<v2>digraph %s {@;" name;
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(* traverse *)
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Enum.iter
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(function
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| Full.EnterVertex (v, attrs, _, _) ->
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Format.fprintf formatter " @[<h>%a [%a];@]@." pp_vertex v
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(Enum.pp ~sep:"," print_attribute) (Enum.of_list attrs)
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| Full.ExitVertex _ -> ()
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| Full.MeetEdge (v2, attrs, v1, _) ->
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Format.fprintf formatter " @[<h>%a -> %a [%a];@]@."
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pp_vertex v1 pp_vertex v2
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(Enum.pp ~sep:"," print_attribute)
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(Enum.of_list attrs))
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events;
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(* close *)
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Format.fprintf formatter "}@]@;@?";
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()
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let pp ~name graph formatter vertices =
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failwith "not implemented"
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let enum = Full.bfs_full graph vertices in
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pp_enum ~name formatter enum
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end
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end
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@ -153,6 +153,10 @@ module type S = sig
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| `Other of string * string
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] (** Dot attribute *)
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val pp_enum : name:string -> Format.formatter ->
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(attribute list,attribute list) Full.traverse_event Enum.t ->
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unit
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val pp : name:string -> (attribute list, attribute list) t ->
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Format.formatter ->
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vertex Enum.t -> unit
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