+
+module Paramod (B : Orderings.Blob) = struct
+ module Pp = Pp.Pp (B)
+ module FU = FoUnif.Founif(B)
+ module IDX = Index.Index(B)
+ module Sup = Superposition.Superposition(B)
+ module Utils = FoUtils.Utils(B)
+ module Order = B
+ module WeightOrderedPassives =
+ struct
+ type t = B.t Terms.passive_clause
+ let compare = Utils.compare_passive_clauses_weight
+ end
+
+ module AgeOrderedPassives =
+ struct
+ type t = B.t Terms.passive_clause
+ let compare = Utils.compare_passive_clauses_age
+ end
+
+ module WeightPassiveSet = Set.Make(WeightOrderedPassives)
+ module AgePassiveSet = Set.Make(AgeOrderedPassives)
+
+ type t = B.t
+ type input = B.input
+ type bag = B.t Terms.bag * int
+ type szsontology =
+ | Unsatisfiable of
+ (B.t Terms.bag * int * B.t Terms.substitution * int list) list
+ | GaveUp
+ | Error of string
+ | Timeout of int * B.t Terms.bag
+ exception Stop of szsontology
+ type state =
+ t Terms.bag
+ * int
+ * Index.Index(B).active_set
+ * (IDX.DT.t * WeightPassiveSet.t * AgePassiveSet.t)
+ * B.t Terms.unit_clause list
+ * (WeightPassiveSet.t * AgePassiveSet.t)
+
+ let empty_state =
+ Terms.empty_bag,
+ 0,
+ ([],IDX.DT.empty),
+ (IDX.DT.empty,WeightPassiveSet.empty,AgePassiveSet.empty),
+ [],
+ (WeightPassiveSet.empty,AgePassiveSet.empty)
+ ;;
+
+ let bag_of_state (bag,n,_,_,_,_) = bag,n
+ ;;
+
+ let replace_bag (_,_,a,b,c,d) (bag,n) = bag,n,a,b,c,d
+ ;;
+
+ let add_passive_clause ?(no_weight=false)
+ (passive_t,passives_w,passives_a) cl =
+ let pcl = if no_weight then (0,cl)
+ else Utils.mk_passive_clause cl in
+ IDX.index_unit_clause passive_t cl,
+ WeightPassiveSet.add pcl passives_w,
+ AgePassiveSet.add pcl passives_a
+ ;;
+
+ let add_passive_goal ?(no_weight=false) (passives_w,passives_a) g =
+ let g = if no_weight then (0,g)
+ else Utils.mk_passive_goal g in
+ WeightPassiveSet.add g passives_w, AgePassiveSet.add g passives_a
+ ;;
+
+ let remove_passive_clause (passive_t,passives_w,passives_a) cl =
+ let passive_t = IDX.remove_unit_clause passive_t (snd cl) in
+ let passives_w = WeightPassiveSet.remove cl passives_w in
+ let passives_a = AgePassiveSet.remove cl passives_a in
+ passive_t,passives_w,passives_a
+ ;;
+
+ let add_passive_clauses ?(no_weight=false) =
+ List.fold_left (add_passive_clause ~no_weight)
+ ;;
+
+ let add_passive_goals ?(no_weight=false)
+ (passives_w,passives_a) new_clauses =
+ let new_clauses_w,new_clauses_a =
+ List.fold_left (add_passive_goal ~no_weight)
+ (WeightPassiveSet.empty,AgePassiveSet.empty) new_clauses
+ in
+ (WeightPassiveSet.union new_clauses_w passives_w,
+ AgePassiveSet.union new_clauses_a passives_a)
+ ;;
+
+ let remove_passive_goal (passives_w,passives_a) cl =
+ let passives_w = WeightPassiveSet.remove cl passives_w in
+ let passives_a = AgePassiveSet.remove cl passives_a in
+ passives_w,passives_a
+ ;;
+
+ let is_passive_set_empty (_,passives_w,passives_a) =
+ if (WeightPassiveSet.is_empty passives_w) then begin
+ assert (AgePassiveSet.is_empty passives_a); true
+ end else begin
+ assert (not (AgePassiveSet.is_empty passives_a)); false
+ end
+ ;;
+
+ let is_passive_g_set_empty (passives_w,passives_a) =
+ if (WeightPassiveSet.is_empty passives_w) then begin
+ assert (AgePassiveSet.is_empty passives_a); true
+ end else begin
+ assert (not (AgePassiveSet.is_empty passives_a)); false
+ end
+ ;;
+
+ let passive_set_cardinal (_,passives_w,_)
+ = WeightPassiveSet.cardinal passives_w
+ ;;
+
+ let g_passive_set_cardinal (passives_w,_)
+ = WeightPassiveSet.cardinal passives_w
+ ;;
+
+ let passive_empty_set =
+ (IDX.DT.empty,WeightPassiveSet.empty,AgePassiveSet.empty)
+ ;;
+
+ let g_passive_empty_set =
+ (WeightPassiveSet.empty,AgePassiveSet.empty)
+ ;;
+
+ let pick_min_passive ~use_age (_,passives_w,passives_a) =
+ if use_age then AgePassiveSet.min_elt passives_a
+ else WeightPassiveSet.min_elt passives_w
+ ;;
+
+ let pick_min_g_passive ~use_age (passives_w,passives_a) =
+ if use_age then AgePassiveSet.min_elt passives_a
+ else WeightPassiveSet.min_elt passives_w
+ ;;
+
+ let mk_unit_clause bag maxvar (t,ty) =
+ let c, maxvar = Utils.mk_unit_clause maxvar (B.embed ty) (B.embed t) in
+ let bag, c = Terms.add_to_bag c bag in
+ (bag, maxvar), c
+ ;;
+
+ let mk_clause bag maxvar (t,ty) =
+ let (proof,ty) = B.saturate t ty in
+ let c, maxvar = Utils.mk_unit_clause maxvar ty proof in
+ let bag, c = Terms.add_to_bag c bag in
+ (bag, maxvar), c
+ ;;
+
+ let mk_passive (bag,maxvar) = mk_clause bag maxvar;;
+
+ let mk_goal (bag,maxvar) = mk_clause bag maxvar;;
+
+ let initialize_goal (bag,maxvar,actives,passives,_,_) t =
+ let (bag,maxvar), g = mk_unit_clause bag maxvar t in
+ let g_passives = g_passive_empty_set in
+ (* if the goal is not an equation we returns an empty
+ passive set *)
+ let g_passives =
+ if Terms.is_eq_clause g then add_passive_goal g_passives g
+ else g_passives
+ in
+ (bag,maxvar,actives,passives,[],g_passives)
+
+
+ (* TODO : global age over facts and goals (without comparing weights) *)
+ let select ~use_age passives g_passives =
+ if is_passive_set_empty passives then begin
+ if (is_passive_g_set_empty g_passives) then
+ raise (Stop GaveUp) (* we say we are incomplete *)
+ else
+ let g_cl = pick_min_g_passive ~use_age:use_age g_passives in
+ (true,g_cl,passives,remove_passive_goal g_passives g_cl)
+ end
+ else let cl = pick_min_passive ~use_age:use_age passives in
+ if is_passive_g_set_empty g_passives then
+ (false,cl,remove_passive_clause passives cl,g_passives)
+ else
+ let g_cl = pick_min_g_passive ~use_age:use_age g_passives in
+ let (id1,_,_,_),(id2,_,_,_) = snd cl, snd g_cl in
+ let cmp = if use_age then id1 <= id2
+ else fst cl <= fst g_cl
+ in
+ if cmp then
+ (false,cl,remove_passive_clause passives cl,g_passives)
+ else
+ (true,g_cl,passives,remove_passive_goal g_passives g_cl)
+ ;;
+
+ let backward_infer_step bag maxvar actives passives
+ g_actives g_passives g_current iterno =
+ (* superposition left, simplifications on goals *)
+ debug (lazy "infer_left step...");
+ let bag, maxvar, new_goals =
+ Sup.infer_left bag maxvar g_current actives
+ in
+ debug (lazy "Performed infer_left step");
+ let bag = Terms.replace_in_bag (g_current,false,iterno) bag in
+ bag, maxvar, actives, passives, g_current::g_actives,
+ (add_passive_goals g_passives new_goals)
+ ;;
+
+ let pp_clauses actives passives =
+ let actives_l, _ = actives in
+ let passive_t,_,_ = passives in
+ let wset = IDX.elems passive_t in
+ ("Actives :" ^ (String.concat ";\n"
+ (List.map Pp.pp_unit_clause actives_l)))
+ ^
+ ("Passives:" ^(String.concat ";\n"
+ (List.map (fun (_,cl) -> Pp.pp_unit_clause cl)
+ (IDX.ClauseSet.elements wset))))
+ ;;
+
+ let forward_infer_step
+ ((bag,maxvar,actives,passives,g_actives,g_passives) as s)
+ current iterno =
+ (* forward step *)
+
+ (* e = select P *
+ * e' = demod A e *
+ * A' = demod [e'] A *
+ * A'' = A' + e' *
+ * e'' = fresh e' *
+ * new = supright e'' A'' *
+ * new'= demod A'' new *
+ * P' = P + new' *)
+ debug (lazy "Forward infer step...");
+ debug (lazy("Number of actives : " ^ (string_of_int (List.length (fst actives)))));
+ noprint (lazy (pp_clauses actives passives));
+ match Sup.keep_simplified current actives bag maxvar
+ with
+ | _,None -> s
+ | bag,Some (current,actives) ->
+ debug (lazy ("simplified to " ^ (Pp.pp_unit_clause current)));
+ let bag, maxvar, actives, new_clauses =
+ Sup.infer_right bag maxvar current actives
+ in
+ debug
+ (lazy
+ ("New clauses :" ^ (String.concat ";\n"
+ (List.map Pp.pp_unit_clause new_clauses))));
+ debug (lazy "Demodulating goals with actives...");
+ (* keep goals demodulated w.r.t. actives and check if solved *)
+ let bag, g_actives =
+ List.fold_left
+ (fun (bag,acc) c ->
+ match
+ Sup.simplify_goal ~no_demod:false maxvar (snd actives) bag acc c
+ with
+ | None -> bag, acc
+ | Some (bag,c1) -> bag,if c==c1 then c::acc else c::c1::acc)
+ (bag,[]) g_actives
+ in
+ let ctable = IDX.index_unit_clause IDX.DT.empty current in
+ let bag, maxvar, new_goals =
+ List.fold_left
+ (fun (bag,m,acc) g ->
+ let bag, m, ng = Sup.infer_left bag m g ([current],ctable) in
+ bag,m,ng@acc)
+ (bag,maxvar,[]) g_actives
+ in
+ let bag = Terms.replace_in_bag (current,false,iterno) bag in
+ (* prerr_endline (Pp.pp_bag bag); *)
+ bag, maxvar, actives,
+ add_passive_clauses passives new_clauses, g_actives,
+ add_passive_goals g_passives new_goals
+ ;;
+
+ let debug_status (_,_,actives,passives,g_actives,g_passives) =
+ lazy
+ ((Printf.sprintf "Number of active goals : %d\n"
+ (List.length g_actives)) ^
+ (Printf.sprintf "Number of passive goals : %d\n"
+ (g_passive_set_cardinal g_passives)) ^
+ (Printf.sprintf "Number of actives : %d\n"
+ (List.length (fst actives))) ^
+ (Printf.sprintf "Number of passives : %d\n"
+ (passive_set_cardinal passives)))
+ ;;
+
+
+ (* we just check if any of the active goals is subsumed by a
+ passive clause, or if any of the passive goal is subsumed
+ by an active or passive clause *)
+ let last_chance (bag,maxvar,actives,passives,g_actives,g_passives) =
+ debug (lazy("Last chance " ^ string_of_float
+ (Unix.gettimeofday())));
+ let actives_l, active_t = actives in
+ let passive_t,wset,_ = passives in
+ let _ = noprint
+ (lazy
+ ("Actives :" ^ (String.concat ";\n"
+ (List.map Pp.pp_unit_clause actives_l)))) in
+ let wset = IDX.elems passive_t in
+ let _ = noprint
+ (lazy
+ ("Passives:" ^(String.concat ";\n"
+ (List.map (fun (_,cl) -> Pp.pp_unit_clause cl)
+ (IDX.ClauseSet.elements wset))))) in
+ let g_passives =
+ WeightPassiveSet.fold
+ (fun (_,x) acc ->
+ if List.exists (Sup.are_alpha_eq x) g_actives then acc
+ else x::acc)
+ (fst g_passives) []
+ in
+ ignore
+ (List.iter
+ (fun x ->
+ ignore
+ (debug (lazy("ckecking goal vs a: " ^ Pp.pp_unit_clause x));
+ Sup.simplify_goal ~no_demod:true maxvar active_t bag [] x))
+ g_passives);
+ ignore
+ (List.iter
+ (fun x ->
+ ignore
+ (debug (lazy("ckecking goal vs p: " ^ Pp.pp_unit_clause x));
+ Sup.simplify_goal ~no_demod:true maxvar passive_t bag [] x))
+ (g_actives@g_passives));
+ raise (Stop (Timeout (maxvar,bag)))
+
+ let check_timeout = function
+ | None -> false
+ | Some timeout -> Unix.gettimeofday () > timeout
+
+ let rec given_clause ~useage
+ bag maxvar iterno weight_picks max_steps timeout
+ actives passives g_actives g_passives
+ =
+ let iterno = iterno + 1 in
+ if iterno = max_steps || check_timeout timeout then
+ last_chance (bag,maxvar,actives,passives,g_actives,g_passives)
+ else
+ let use_age = useage && (weight_picks = (iterno / 6 + 1)) in
+ let weight_picks = if use_age then 0 else weight_picks+1
+ in
+
+ let rec aux_select bag
+ (passives:IDX.DT.t * WeightPassiveSet.t * AgePassiveSet.t)
+ g_passives =
+ let backward,(weight,current),passives,g_passives =
+ select ~use_age passives g_passives
+ in
+ if use_age && weight > monster then
+ let bag,cl = Terms.add_to_bag current bag in
+ if backward then
+ aux_select bag passives (add_passive_goal g_passives cl)
+ else
+ aux_select bag (add_passive_clause passives cl) g_passives
+ else
+ let bag = Terms.replace_in_bag (current,false,iterno) bag in
+ if backward then
+ let _ = debug (lazy("Selected goal : " ^ Pp.pp_unit_clause current)) in
+ match
+ Sup.simplify_goal
+ ~no_demod:false maxvar (snd actives) bag g_actives current
+ with
+ | None -> aux_select bag passives g_passives
+ | Some (bag,g_current) ->
+ backward_infer_step bag maxvar actives passives
+ g_actives g_passives g_current iterno
+ else
+ let _ = debug (lazy("Selected fact : " ^ Pp.pp_unit_clause current))
+ in
+ if Sup.orphan_murder bag (fst actives) current then
+ let _ = debug (lazy "Orphan murdered") in
+ let bag = Terms.replace_in_bag (current,true,iterno) bag in
+ aux_select bag passives g_passives
+ else
+ let s = bag,maxvar,actives,passives,g_actives,g_passives in
+ let s1 = forward_infer_step s current iterno
+ in
+ if s == s1 then aux_select bag passives g_passives
+ else s1
+ in
+ (*prerr_endline "Active table :";
+ (List.iter (fun x -> prerr_endline (Pp.pp_unit_clause x))
+ (fst actives)); *)
+
+ let (bag,maxvar,actives,passives,g_actives,g_passives) as status =
+ aux_select bag passives g_passives
+ in
+ debug (debug_status status);
+ given_clause ~useage
+ bag maxvar iterno weight_picks max_steps timeout
+ actives passives g_actives g_passives
+ ;;
+
+ let check_and_infer ~no_demod iterno status current =
+ let bag,maxvar,actives,passives,g_actives,g_passives = status in
+ match
+ Sup.simplify_goal
+ ~no_demod maxvar (snd actives) bag g_actives current
+ with
+ | None -> debug (lazy "None"); status
+ | Some (bag,g_current) ->
+ let _ =
+ debug (lazy("Infer on goal : "
+ ^ Pp.pp_unit_clause g_current))
+ in
+ backward_infer_step bag maxvar actives passives
+ g_actives g_passives g_current iterno
+
+ (* similar to given_clause, but it merely works on goals,
+ in parallel, at each iteration *)
+ let rec goal_narrowing iterno max_steps timeout status
+ =
+ debug (debug_status status);
+ let iterno = iterno + 1 in
+ if iterno = max_steps || check_timeout timeout then
+ last_chance status
+ else
+ let _,_,_,_,_,g_passives = status in
+ let passive_goals = WeightPassiveSet.elements (fst g_passives) in
+ let newstatus =
+ List.fold_left
+ (fun acc g ->
+ let bag,maxvar,actives,passives,g_actives,g_passives = acc in
+ let g_passives =
+ remove_passive_goal g_passives g in
+ let current = snd g in
+ let _ =
+ debug (lazy("Selected goal : " ^ Pp.pp_unit_clause current))
+ in
+ (* we work both on the original goal and the demodulated one*)
+ let acc = check_and_infer ~no_demod:false iterno acc current
+ in check_and_infer ~no_demod:true iterno acc current)
+ status passive_goals
+ in
+ goal_narrowing iterno max_steps timeout newstatus
+
+ let compute_result bag i subst =
+ let l =
+ let rec traverse ongoal (accg,acce) i =
+ match Terms.get_from_bag i bag with
+ | (id,_,_,Terms.Exact _),_,_ ->
+ if ongoal then [i],acce else
+ if (List.mem i acce) then accg,acce else accg,acce@[i]
+ | (_,_,_,Terms.Step (_,i1,i2,_,_,_)),_,_ ->
+ if (not ongoal) && (List.mem i acce) then accg,acce
+ else
+ let accg,acce =
+ traverse false (traverse ongoal (accg,acce) i1) i2
+ in
+ if ongoal then i::accg,acce else accg,i::acce
+ in
+ let gsteps,esteps = traverse true ([],[]) i in
+ (List.rev esteps)@gsteps
+ in
+ debug (lazy ("steps: " ^ (string_of_int (List.length l))));
+ let max_w =
+ List.fold_left
+ (fun acc i ->
+ let (cl,_,_) = Terms.get_from_bag i bag in
+ max acc (Order.compute_unit_clause_weight cl)) 0 l in
+ debug (lazy ("Max weight : " ^ (string_of_int max_w)));
+(* List.iter (fun id -> let ((_,lit,_,proof as cl),d,it) =
+ Terms.get_from_bag id bag in
+ if d then
+ prerr_endline
+ (Printf.sprintf "Id : %d, selected at %d, weight %d,disc, by %s"
+ id it (Order.compute_unit_clause_weight cl)
+ (Pp.pp_proof_step proof))
+ else
+ prerr_endline
+ (Printf.sprintf "Id : %d, selected at %d, weight %d by %s"
+ id it (Order.compute_unit_clause_weight cl)
+ (Pp.pp_proof_step proof))) l;*)
+ debug (lazy ("Proof:" ^
+ (String.concat "\n"
+ (List.map
+ (fun x ->
+ let cl,_,_ = Terms.get_from_bag x bag in
+ Pp.pp_unit_clause cl) l))));
+ Unsatisfiable [ bag, i, subst, l ]
+
+ let paramod ~useage ~max_steps ?timeout (bag,maxvar) ~g_passives ~passives =
+ let _initial_timestamp = Unix.gettimeofday () in
+ let passives =
+ add_passive_clauses ~no_weight:true passive_empty_set passives
+ in
+ let g_passives =
+ add_passive_goals ~no_weight:true g_passive_empty_set g_passives
+ in
+ let g_actives = [] in
+ let actives = [], IDX.DT.empty in
+ try
+ given_clause ~useage ~noinfer:false
+ bag maxvar 0 0 max_steps timeout actives passives g_actives g_passives
+ with
+ | Sup.Success (bag, _, (i,_,_,_),subst) ->
+ compute_result bag i subst
+ | Stop (Unsatisfiable _) -> Error "solution found!"
+ | Stop o -> o
+ ;;
+
+let demod s goal =
+ let bag,maxvar,actives,passives,g_actives,g_passives = s in
+ let (bag,maxvar), g = mk_goal (bag,maxvar) goal in
+ let bag, ((i,_,_,_) as g1) = Sup.demodulate bag g (snd actives) in
+ if g1 = g then GaveUp else compute_result bag i []