+
+(* returns an estimation of how many equalities in passive can be activated
+ within the current time limit *)
+let get_selection_estimate () =
+ elapsed_time := (Unix.gettimeofday ()) -. !start_time;
+ (* !processed_clauses * (int_of_float (!time_limit /. !elapsed_time)) *)
+ int_of_float (
+ ceil ((float_of_int !processed_clauses) *.
+ ((!time_limit (* *. 2. *)) /. !elapsed_time -. 1.)))
+;;
+
+
+(** initializes the set of goals *)
+let make_goals goal =
+ let active = []
+ and passive = [0, [goal]] in
+ active, passive
+;;
+
+
+(** initializes the set of theorems *)
+let make_theorems theorems =
+ theorems, []
+;;
+
+
+let activate_goal (active, passive) =
+ match passive with
+ | goal_conj::tl -> true, (goal_conj::active, tl)
+ | [] -> false, (active, passive)
+;;
+
+
+let activate_theorem (active, passive) =
+ match passive with
+ | theorem::tl -> true, (theorem::active, tl)
+ | [] -> false, (active, passive)
+;;
+
+
+(** simplifies a goal with equalities in active and passive *)
+let simplify_goal env goal ?passive (active_list, active_table) =
+ let pl, passive_table =
+ match passive with
+ | None -> [], None
+ | Some ((pn, _), (pp, _), pt) ->
+ let pn = List.map (fun e -> (Negative, e)) pn
+ and pp = List.map (fun e -> (Positive, e)) pp in
+ pn @ pp, Some pt
+ in
+ let all = if pl = [] then active_list else active_list @ pl in
+
+ let demodulate table goal =
+ let newmeta, newgoal =
+ Indexing.demodulation_goal !maxmeta env table goal in
+ maxmeta := newmeta;
+ goal != newgoal, newgoal
+ in
+ let changed, goal =
+ match passive_table with
+ | None -> demodulate active_table goal
+ | Some passive_table ->
+ let changed, goal = demodulate active_table goal in
+ let changed', goal = demodulate passive_table goal in
+ (changed || changed'), goal
+ in
+ changed, goal
+;;
+
+
+let simplify_goals env goals ?passive active =
+ let a_goals, p_goals = goals in
+ let p_goals =
+ List.map
+ (fun (d, gl) ->
+ let gl =
+ List.map (fun g -> snd (simplify_goal env g ?passive active)) gl in
+ d, gl)
+ p_goals
+ in
+ let goals =
+ List.fold_left
+ (fun (a, p) (d, gl) ->
+ let changed = ref false in
+ let gl =
+ List.map
+ (fun g ->
+ let c, g = simplify_goal env g ?passive active in
+ changed := !changed || c; g) gl in
+ if !changed then (a, (d, gl)::p) else ((d, gl)::a, p))
+ ([], p_goals) a_goals
+ in
+ goals
+;;
+
+
+let simplify_theorems env theorems ?passive (active_list, active_table) =
+ let pl, passive_table =
+ match passive with
+ | None -> [], None
+ | Some ((pn, _), (pp, _), pt) ->
+ let pn = List.map (fun e -> (Negative, e)) pn
+ and pp = List.map (fun e -> (Positive, e)) pp in
+ pn @ pp, Some pt
+ in
+ let all = if pl = [] then active_list else active_list @ pl in
+ let a_theorems, p_theorems = theorems in
+ let demodulate table theorem =
+ let newmeta, newthm =
+ Indexing.demodulation_theorem !maxmeta env table theorem in
+ maxmeta := newmeta;
+ theorem != newthm, newthm
+ in
+ let foldfun table (a, p) theorem =
+ let changed, theorem = demodulate table theorem in
+ if changed then (a, theorem::p) else (theorem::a, p)
+ in
+ let mapfun table theorem = snd (demodulate table theorem) in
+ match passive_table with
+ | None ->
+ let p_theorems = List.map (mapfun active_table) p_theorems in
+ List.fold_left (foldfun active_table) ([], p_theorems) a_theorems
+ | Some passive_table ->
+ let p_theorems = List.map (mapfun active_table) p_theorems in
+ let p_theorems, a_theorems =
+ List.fold_left (foldfun active_table) ([], p_theorems) a_theorems in
+ let p_theorems = List.map (mapfun passive_table) p_theorems in
+ List.fold_left (foldfun passive_table) ([], p_theorems) a_theorems
+;;
+
+
+(* applies equality to goal to see if the goal can be closed *)
+let apply_equality_to_goal env equality goal =
+ let module C = Cic in
+ let module HL = HelmLibraryObjects in
+ let module I = Inference in
+ let metasenv, context, ugraph = env in
+ let _, proof, (ty, left, right, _), metas, args = equality in
+ let eqterm =
+ C.Appl [C.MutInd (LibraryObjects.eq_URI (), 0, []); ty; left; right] in
+ let gproof, gmetas, gterm = goal in
+(* debug_print *)
+(* (lazy *)
+(* (Printf.sprintf "APPLY EQUALITY TO GOAL: %s, %s" *)
+(* (string_of_equality equality) (CicPp.ppterm gterm))); *)
+ try
+ let subst, metasenv', _ =
+ let menv = metasenv @ metas @ gmetas in
+ Inference.unification menv context eqterm gterm ugraph
+ in
+ let newproof =
+ match proof with
+ | I.BasicProof t -> I.BasicProof (CicMetaSubst.apply_subst subst t)
+ | I.ProofBlock (s, uri, nt, t, pe, p) ->
+ I.ProofBlock (subst @ s, uri, nt, t, pe, p)
+ | _ -> assert false
+ in
+ let newgproof =
+ let rec repl = function
+ | I.ProofGoalBlock (_, gp) -> I.ProofGoalBlock (newproof, gp)
+ | I.NoProof -> newproof
+ | I.BasicProof p -> newproof
+ | I.SubProof (t, i, p) -> I.SubProof (t, i, repl p)
+ | _ -> assert false
+ in
+ repl gproof
+ in
+ true, subst, newgproof
+ with CicUnification.UnificationFailure _ ->
+ false, [], I.NoProof
+;;
+
+
+
+let new_meta metasenv =
+ let m = CicMkImplicit.new_meta metasenv [] in
+ incr maxmeta;
+ while !maxmeta <= m do incr maxmeta done;
+ !maxmeta
+;;
+
+
+(* applies a theorem or an equality to goal, returning a list of subgoals or
+ an indication of failure *)
+let apply_to_goal env theorems ?passive active goal =
+ let metasenv, context, ugraph = env in
+ let proof, metas, term = goal in
+ (* debug_print *)
+ (* (lazy *)
+ (* (Printf.sprintf "apply_to_goal with goal: %s" *)
+ (* (\* (string_of_proof proof) *\)(CicPp.ppterm term))); *)
+ let status =
+ let irl =
+ CicMkImplicit.identity_relocation_list_for_metavariable context in
+ let proof', newmeta =
+ let rec get_meta = function
+ | SubProof (t, i, p) ->
+ let t', i' = get_meta p in
+ if i' = -1 then t, i else t', i'
+ | ProofGoalBlock (_, p) -> get_meta p
+ | _ -> Cic.Implicit None, -1
+ in
+ let p, m = get_meta proof in
+ if m = -1 then
+ let n = new_meta (metasenv @ metas) in
+ Cic.Meta (n, irl), n
+ else
+ p, m
+ in
+ let metasenv = (newmeta, context, term)::metasenv @ metas in
+ let bit = new_meta metasenv, context, term in
+ let metasenv' = bit::metasenv in
+ ((None, metasenv', Cic.Meta (newmeta, irl), term), newmeta)
+ in
+ let rec aux = function
+ | [] -> `No
+ | (theorem, thmty, _)::tl ->
+ try
+ let subst, (newproof, newgoals) =
+ PrimitiveTactics.apply_tac_verbose_with_subst ~term:theorem status
+ in
+ if newgoals = [] then
+ let _, _, p, _ = newproof in
+ let newp =
+ let rec repl = function
+ | Inference.ProofGoalBlock (_, gp) ->
+ Inference.ProofGoalBlock (Inference.BasicProof p, gp)
+ | Inference.NoProof -> Inference.BasicProof p
+ | Inference.BasicProof _ -> Inference.BasicProof p
+ | Inference.SubProof (t, i, p2) ->
+ Inference.SubProof (t, i, repl p2)
+ | _ -> assert false
+ in
+ repl proof
+ in
+ let _, m = status in
+ let subst = List.filter (fun (i, _) -> i = m) subst in
+ `Ok (subst, [newp, metas, term])
+ else
+ let _, menv, p, _ = newproof in
+ let irl =
+ CicMkImplicit.identity_relocation_list_for_metavariable context
+ in
+ let goals =
+ List.map
+ (fun i ->
+ let _, _, ty = CicUtil.lookup_meta i menv in
+ let p' =
+ let rec gp = function
+ | SubProof (t, i, p) ->
+ SubProof (t, i, gp p)
+ | ProofGoalBlock (sp1, sp2) ->
+ ProofGoalBlock (sp1, gp sp2)
+ | BasicProof _
+ | NoProof ->
+ SubProof (p, i, BasicProof (Cic.Meta (i, irl)))
+ | ProofSymBlock (s, sp) ->
+ ProofSymBlock (s, gp sp)
+ | ProofBlock (s, u, nt, t, pe, sp) ->
+ ProofBlock (s, u, nt, t, pe, gp sp)
+ in gp proof
+ in
+ (p', menv, ty))
+ newgoals
+ in
+ let goals =
+ let weight t =
+ let w, m = weight_of_term t in
+ w + 2 * (List.length m)
+ in
+ List.sort
+ (fun (_, _, t1) (_, _, t2) ->
+ Pervasives.compare (weight t1) (weight t2))
+ goals
+ in
+ let best = aux tl in
+ match best with
+ | `Ok (_, _) -> best
+ | `No -> `GoOn ([subst, goals])
+ | `GoOn sl -> `GoOn ((subst, goals)::sl)
+ with ProofEngineTypes.Fail msg ->
+ aux tl
+ in
+ let r, s, l =
+ if Inference.term_is_equality term then
+ let rec appleq_a = function
+ | [] -> false, [], []
+ | (Positive, equality)::tl ->
+ let ok, s, newproof = apply_equality_to_goal env equality goal in
+ if ok then true, s, [newproof, metas, term] else appleq_a tl
+ | _::tl -> appleq_a tl
+ in
+ let rec appleq_p = function
+ | [] -> false, [], []
+ | equality::tl ->
+ let ok, s, newproof = apply_equality_to_goal env equality goal in
+ if ok then true, s, [newproof, metas, term] else appleq_p tl
+ in
+ let al, _ = active in
+ match passive with
+ | None -> appleq_a al
+ | Some (_, (pl, _), _) ->
+ let r, s, l = appleq_a al in if r then r, s, l else appleq_p pl
+ else
+ false, [], []
+ in
+ if r = true then `Ok (s, l) else aux theorems
+;;
+
+
+(* sorts a conjunction of goals in order to detect earlier if it is
+ unsatisfiable. Non-predicate goals are placed at the end of the list *)
+let sort_goal_conj (metasenv, context, ugraph) (depth, gl) =
+ let gl =
+ List.stable_sort
+ (fun (_, e1, g1) (_, e2, g2) ->
+ let ty1, _ =
+ CicTypeChecker.type_of_aux' (e1 @ metasenv) context g1 ugraph
+ and ty2, _ =
+ CicTypeChecker.type_of_aux' (e2 @ metasenv) context g2 ugraph
+ in
+ let prop1 =
+ let b, _ =
+ CicReduction.are_convertible context (Cic.Sort Cic.Prop) ty1 ugraph
+ in
+ if b then 0 else 1
+ and prop2 =
+ let b, _ =
+ CicReduction.are_convertible context (Cic.Sort Cic.Prop) ty2 ugraph
+ in
+ if b then 0 else 1
+ in
+ if prop1 = 0 && prop2 = 0 then
+ let e1 = if Inference.term_is_equality g1 then 0 else 1
+ and e2 = if Inference.term_is_equality g2 then 0 else 1 in
+ e1 - e2
+ else
+ prop1 - prop2)
+ gl
+ in
+ (depth, gl)
+;;
+
+
+let is_meta_closed goals =
+ List.for_all (fun (_, _, g) -> CicUtil.is_meta_closed g) goals
+;;
+
+
+(* applies a series of theorems/equalities to a conjunction of goals *)
+let rec apply_to_goal_conj env theorems ?passive active (depth, goals) =
+ let aux (goal, r) tl =
+ let propagate_subst subst (proof, metas, term) =
+ let rec repl = function
+ | NoProof -> NoProof
+ | BasicProof t ->
+ BasicProof (CicMetaSubst.apply_subst subst t)
+ | ProofGoalBlock (p, pb) ->
+ let pb' = repl pb in
+ ProofGoalBlock (p, pb')
+ | SubProof (t, i, p) ->
+ let t' = CicMetaSubst.apply_subst subst t in
+ let p = repl p in
+ SubProof (t', i, p)
+ | ProofSymBlock (ens, p) -> ProofSymBlock (ens, repl p)
+ | ProofBlock (s, u, nty, t, pe, p) ->
+ ProofBlock (subst @ s, u, nty, t, pe, p)
+ in (repl proof, metas, term)
+ in
+ (* let r = apply_to_goal env theorems ?passive active goal in *) (
+ match r with
+ | `No -> `No (depth, goals)
+ | `GoOn sl ->
+ let l =
+ List.map
+ (fun (s, gl) ->
+ let tl = List.map (propagate_subst s) tl in
+ sort_goal_conj env (depth+1, gl @ tl)) sl
+ in
+ `GoOn l
+ | `Ok (subst, gl) ->
+ if tl = [] then
+ `Ok (depth, gl)
+ else
+ let p, _, _ = List.hd gl in
+ let subproof =
+ let rec repl = function
+ | SubProof (_, _, p) -> repl p
+ | ProofGoalBlock (p1, p2) ->
+ ProofGoalBlock (repl p1, repl p2)
+ | p -> p
+ in
+ build_proof_term (repl p)
+ in
+ let i =
+ let rec get_meta = function
+ | SubProof (_, i, p) ->
+ let i' = get_meta p in
+ if i' = -1 then i else i'
+(* max i (get_meta p) *)
+ | ProofGoalBlock (_, p) -> get_meta p
+ | _ -> -1
+ in
+ get_meta p
+ in
+ let subst =
+ let _, (context, _, _) = List.hd subst in
+ [i, (context, subproof, Cic.Implicit None)]
+ in
+ let tl = List.map (propagate_subst subst) tl in
+ let conj = sort_goal_conj env (depth(* +1 *), tl) in
+ `GoOn ([conj])
+ )
+ in
+ if depth > !maxdepth || (List.length goals) > !maxwidth then
+ `No (depth, goals)
+ else
+ let rec search_best res = function
+ | [] -> res
+ | goal::tl ->
+ let r = apply_to_goal env theorems ?passive active goal in
+ match r with
+ | `Ok _ -> (goal, r)
+ | `No -> search_best res tl
+ | `GoOn l ->
+ let newres =
+ match res with
+ | _, `Ok _ -> assert false
+ | _, `No -> goal, r
+ | _, `GoOn l2 ->
+ if (List.length l) < (List.length l2) then goal, r else res
+ in
+ search_best newres tl
+ in
+ let hd = List.hd goals in
+ let res = hd, (apply_to_goal env theorems ?passive active hd) in
+ let best =
+ match res with
+ | _, `Ok _ -> res
+ | _, _ -> search_best res (List.tl goals)
+ in
+ let res = aux best (List.filter (fun g -> g != (fst best)) goals) in
+ match res with
+ | `GoOn ([conj]) when is_meta_closed (snd conj) &&
+ (List.length (snd conj)) < (List.length goals)->
+ apply_to_goal_conj env theorems ?passive active conj
+ | _ -> res
+;;
+
+
+(*
+module OrderedGoals = struct
+ type t = int * (Inference.proof * Cic.metasenv * Cic.term) list
+
+ let compare g1 g2 =
+ let d1, l1 = g1
+ and d2, l2 = g2 in
+ let r = d2 - d1 in
+ if r <> 0 then r
+ else let r = (List.length l1) - (List.length l2) in
+ if r <> 0 then r
+ else
+ let res = ref 0 in
+ let _ =
+ List.exists2
+ (fun (_, _, t1) (_, _, t2) ->
+ let r = Pervasives.compare t1 t2 in
+ if r <> 0 then (
+ res := r;
+ true
+ ) else
+ false) l1 l2
+ in !res
+end
+
+module GoalsSet = Set.Make(OrderedGoals);;
+
+
+exception SearchSpaceOver;;
+*)
+
+
+(*
+let apply_to_goals env is_passive_empty theorems active goals =
+ debug_print (lazy "\n\n\tapply_to_goals\n\n");
+ let add_to set goals =
+ List.fold_left (fun s g -> GoalsSet.add g s) set goals
+ in
+ let rec aux set = function
+ | [] ->
+ debug_print (lazy "HERE!!!");
+ if is_passive_empty then raise SearchSpaceOver else false, set
+ | goals::tl ->
+ let res = apply_to_goal_conj env theorems active goals in
+ match res with
+ | `Ok newgoals ->
+ let _ =
+ let d, p, t =
+ match newgoals with
+ | (d, (p, _, t)::_) -> d, p, t
+ | _ -> assert false
+ in
+ debug_print
+ (lazy
+ (Printf.sprintf "\nOK!!!!\ndepth: %d\nProof: %s\ngoal: %s\n"
+ d (string_of_proof p) (CicPp.ppterm t)))
+ in
+ true, GoalsSet.singleton newgoals
+ | `GoOn newgoals ->
+ let set' = add_to set (goals::tl) in
+ let set' = add_to set' newgoals in
+ false, set'
+ | `No newgoals ->
+ aux set tl
+ in
+ let n = List.length goals in
+ let res, goals = aux (add_to GoalsSet.empty goals) goals in
+ let goals = GoalsSet.elements goals in
+ debug_print (lazy "\n\tapply_to_goals end\n");
+ let m = List.length goals in
+ if m = n && is_passive_empty then
+ raise SearchSpaceOver
+ else
+ res, goals
+;;
+*)
+
+
+(* sorts the list of passive goals to minimize the search for a proof (doesn't
+ work that well yet...) *)
+let sort_passive_goals goals =
+ List.stable_sort
+ (fun (d1, l1) (d2, l2) ->
+ let r1 = d2 - d1
+ and r2 = (List.length l1) - (List.length l2) in
+ let foldfun ht (_, _, t) =
+ let _ = List.map (fun i -> Hashtbl.replace ht i 1) (metas_of_term t)
+ in ht
+ in
+ let m1 = Hashtbl.length (List.fold_left foldfun (Hashtbl.create 3) l1)
+ and m2 = Hashtbl.length (List.fold_left foldfun (Hashtbl.create 3) l2)
+ in let r3 = m1 - m2 in
+ if r3 <> 0 then r3
+ else if r2 <> 0 then r2
+ else r1)
+ (* let _, _, g1 = List.hd l1 *)
+(* and _, _, g2 = List.hd l2 in *)
+(* let e1 = if Inference.term_is_equality g1 then 0 else 1 *)
+(* and e2 = if Inference.term_is_equality g2 then 0 else 1 *)
+(* in let r4 = e1 - e2 in *)
+(* if r4 <> 0 then r3 else r1) *)
+ goals
+;;
+
+
+let print_goals goals =
+ (String.concat "\n"
+ (List.map
+ (fun (d, gl) ->
+ let gl' =
+ List.map
+ (fun (p, _, t) ->
+ (* (string_of_proof p) ^ ", " ^ *) (CicPp.ppterm t)) gl
+ in
+ Printf.sprintf "%d: %s" d (String.concat "; " gl')) goals))
+;;
+
+
+(* tries to prove the first conjunction in goals with applications of
+ theorems/equalities, returning new sub-goals or an indication of success *)
+let apply_goal_to_theorems dbd env theorems ?passive active goals =
+ let theorems, _ = theorems in
+ let a_goals, p_goals = goals in
+ let goal = List.hd a_goals in
+ let not_in_active gl =
+ not
+ (List.exists
+ (fun (_, gl') ->
+ if (List.length gl) = (List.length gl') then
+ List.for_all2 (fun (_, _, g1) (_, _, g2) -> g1 = g2) gl gl'
+ else
+ false)
+ a_goals)
+ in
+ let aux theorems =
+ let res = apply_to_goal_conj env theorems ?passive active goal in
+ match res with
+ | `Ok newgoals ->
+ true, ([newgoals], [])
+ | `No _ ->
+ false, (a_goals, p_goals)
+ | `GoOn newgoals ->
+ let newgoals =
+ List.filter
+ (fun (d, gl) ->
+ (d <= !maxdepth) && (List.length gl) <= !maxwidth &&
+ not_in_active gl)
+ newgoals in
+ let p_goals = newgoals @ p_goals in
+ let p_goals = sort_passive_goals p_goals in
+ false, (a_goals, p_goals)
+ in
+ aux theorems
+;;
+
+
+let apply_theorem_to_goals env theorems active goals =
+ let a_goals, p_goals = goals in
+ let theorem = List.hd (fst theorems) in
+ let theorems = [theorem] in
+ let rec aux p = function
+ | [] -> false, ([], p)
+ | goal::tl ->
+ let res = apply_to_goal_conj env theorems active goal in
+ match res with
+ | `Ok newgoals -> true, ([newgoals], [])
+ | `No _ -> aux p tl
+ | `GoOn newgoals -> aux (newgoals @ p) tl
+ in
+ let ok, (a, p) = aux p_goals a_goals in
+ if ok then
+ ok, (a, p)
+ else
+ let p_goals =
+ List.stable_sort
+ (fun (d1, l1) (d2, l2) ->
+ let r = d2 - d1 in
+ if r <> 0 then r
+ else let r = (List.length l1) - (List.length l2) in
+ if r <> 0 then r
+ else
+ let res = ref 0 in
+ let _ =
+ List.exists2
+ (fun (_, _, t1) (_, _, t2) ->
+ let r = Pervasives.compare t1 t2 in
+ if r <> 0 then (res := r; true) else false) l1 l2
+ in !res)
+ p
+ in
+ ok, (a_goals, p_goals)
+;;
+
+
+(* given-clause algorithm with lazy reduction strategy *)
+let rec given_clause dbd env goals theorems passive active =
+ let goals = simplify_goals env goals active in
+ let ok, goals = activate_goal goals in
+ (* let theorems = simplify_theorems env theorems active in *)
+ if ok then
+ let ok, goals = apply_goal_to_theorems dbd env theorems active goals in
+ if ok then
+ let proof =
+ match (fst goals) with
+ | (_, [proof, _, _])::_ -> Some proof
+ | _ -> assert false
+ in
+ ParamodulationSuccess (proof, env)
+ else
+ given_clause_aux dbd env goals theorems passive active
+ else
+(* let ok', theorems = activate_theorem theorems in *)
+ let ok', theorems = false, theorems in
+ if ok' then
+ let ok, goals = apply_theorem_to_goals env theorems active goals in
+ if ok then
+ let proof =
+ match (fst goals) with
+ | (_, [proof, _, _])::_ -> Some proof
+ | _ -> assert false
+ in
+ ParamodulationSuccess (proof, env)
+ else
+ given_clause_aux dbd env goals theorems passive active
+ else
+ if (passive_is_empty passive) then ParamodulationFailure
+ else given_clause_aux dbd env goals theorems passive active
+
+and given_clause_aux dbd env goals theorems passive active =
+ let time1 = Unix.gettimeofday () in
+
+ let selection_estimate = get_selection_estimate () in
+ let kept = size_of_passive passive in
+ let passive =
+ if !time_limit = 0. || !processed_clauses = 0 then
+ passive
+ else if !elapsed_time > !time_limit then (
+ debug_print (lazy (Printf.sprintf "Time limit (%.2f) reached: %.2f\n"
+ !time_limit !elapsed_time));
+ make_passive [] []
+ ) else if kept > selection_estimate then (
+ debug_print
+ (lazy (Printf.sprintf ("Too many passive equalities: pruning..." ^^
+ "(kept: %d, selection_estimate: %d)\n")
+ kept selection_estimate));
+ prune_passive selection_estimate active passive
+ ) else
+ passive
+ in
+
+ let time2 = Unix.gettimeofday () in
+ passive_maintainance_time := !passive_maintainance_time +. (time2 -. time1);
+
+ kept_clauses := (size_of_passive passive) + (size_of_active active);