Source file hlt_elim.ml
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open Logtk
open Libzipperposition
module T = Term
module Ty = Type
module Lits = Literals
module Lit = Literal
module A = Libzipperposition_avatar
let section = Util.Section.make ~parent:Const.section "hlt-elim"
let k_enabled = Flex_state.create_key ()
let k_max_depth = Flex_state.create_key ()
let k_simpl_new = Flex_state.create_key ()
let k_clauses_to_track = Flex_state.create_key ()
let k_max_self_impls = Flex_state.create_key ()
let k_unit_propagated_hle = Flex_state.create_key ()
let k_reduce_tautologies = Flex_state.create_key ()
let k_delete_lits = Flex_state.create_key ()
let k_max_tracked_clauses = Flex_state.create_key ()
let k_track_eq = Flex_state.create_key ()
let k_insert_only_ordered = Flex_state.create_key ()
let k_heartbeat_steps = Flex_state.create_key ()
let k_heartbeat_disabled_hlbe = Flex_state.create_key ()
let k_max_imp_entries = Flex_state.create_key ()
let k_basic_rules = Flex_state.create_key ()
let k_penalize_tautologies = Flex_state.create_key ()
module type S = sig
module Env : Env.S
module C : module type of Env.C
(** {5 Registration} *)
val setup : unit -> unit
end
module Make(E : Env.S) : S with module Env = E = struct
module Env = E
module C = Env.C
module CS = C.ClauseSet
module L = Literal
module PremiseIdx = NPDtree.MakeTerm(struct
type t = (CS.t T.Tbl.t) * bool
let compare (a1,_) (a2,_) = compare (T.Tbl.length a1) (T.Tbl.length a2)
end)
module ConclusionIdx = NPDtree.MakeTerm(struct
type t = T.t
let compare = Term.compare
end)
module UnitIdx = NPDtree.MakeTerm(struct
type t = C.t
let compare = C.compare
end)
type propagation_kind = Failed | UnitPropagated
module PropagatedLitsIdx = NPDtree.MakeTerm(struct
type t = CS.t * propagation_kind
let compare (a,_) (b,_) = CS.compare a b
end)
exception RuleNotApplicable
let prems_ = ref (PremiseIdx.empty ())
let concls_ = ref (ConclusionIdx.empty ())
let units_ = ref (UnitIdx.empty ())
let propagated_ = ref (PropagatedLitsIdx.empty ())
let propagated_size_ = ref 0
let cl_occs = ref Util.Int_map.empty
let tracked_binary = ref 0
let tracked_unary = ref 0
let heartbeat_ = ref false
let is_tauto c =
Literals.is_trivial (C.lits c) || Trail.is_trivial (C.trail c)
let [@inline] tracking_eq () =
Env.flex_get k_track_eq
let idx_sc, q_sc = 0, 1
let should_update_propagated () =
Env.flex_get k_unit_propagated_hle &&
!propagated_size_ <= (Env.flex_get k_max_tracked_clauses)
let app_subst ?(sc=idx_sc) ~subst t =
Subst.FO.apply Subst.Renaming.none subst (t,sc)
let register_conclusion ~tbl ~premise concl proofset =
if not @@ T.Tbl.mem tbl concl && T.depth concl <= 4 then (
T.Tbl.replace tbl concl proofset;
concls_ := ConclusionIdx.add !concls_ concl premise)
let iter_ctx a b k =
let common_arg xs ys =
let rec aux acc xs ys =
match xs with
| x :: xs' ->
begin match ys with
| y :: ys' ->
if (not (T.equal x y)) && CCOpt.is_none acc then (
aux (Some (x,y)) xs' ys'
) else if T.equal x y then aux acc xs' ys'
else None
| _ -> assert false
end
| _ ->
(assert (CCList.is_empty ys));
acc
in
aux None xs ys
in
let rec aux a b =
match T.view a, T.view b with
| T.App(hda, argsa), T.App(hdb, argsb)
when Type.equal (T.ty a) (T.ty b) ->
if T.is_const hda && T.equal hda hdb then (
match common_arg argsa argsb with
| Some (a, b) ->
k (a, b);
aux a b
| None -> ()
)
| _ -> ()
in
aux a b
let retrieve_idx ~getter (premise, q_sc) =
match T.view premise with
| T.AppBuiltin(Builtin.Eq, ([_;a;b]|[a;b])) when tracking_eq () ->
Iter.append (getter (premise, q_sc)) (getter ((T.Form.eq b a), q_sc))
| T.AppBuiltin(Builtin.Neq, ([_;a;b]|[a;b])) when tracking_eq () ->
Iter.append (getter (premise, q_sc)) (getter ((T.Form.neq b a), q_sc))
| _ -> getter (premise, q_sc)
let retrieve_gen_prem_idx () =
retrieve_idx ~getter:(PremiseIdx.retrieve_generalizations (!prems_, idx_sc))
let retrieve_spec_prem_idx () =
retrieve_idx ~getter:(PremiseIdx.retrieve_specializations (!prems_, idx_sc))
let retrieve_gen_concl_idx () =
retrieve_idx ~getter:(ConclusionIdx.retrieve_generalizations (!concls_,idx_sc))
let retrieve_spec_concl_idx () =
retrieve_idx ~getter:(ConclusionIdx.retrieve_specializations (!concls_,idx_sc))
let retrieve_gen_unit_idx unit_sc =
retrieve_idx ~getter:(UnitIdx.retrieve_generalizations (!units_, unit_sc))
let [@inline] get_predicate lit =
match lit with
| L.Equation(lhs,_,_) when L.is_predicate_lit lit ->
Some (lhs, Lit.is_positivoid lit)
| L.Equation(lhs,rhs,sign) when tracking_eq () ->
Some (T.Form.eq lhs rhs, sign)
| _ -> None
let [@inline] matching_eq ?(decompose=false) ~subst ~pattern (t, sc) =
let try_decompositions ?(cons=T.Form.eq) a b =
iter_ctx a b
|> Iter.find (fun (a, b) ->
try
Some (Unif.FO.matching ~subst ~pattern (cons a b, sc))
with Unif.Fail ->
begin
try
Some (Unif.FO.matching ~subst ~pattern (cons b a, sc))
with Unif.Fail -> None
end)
|> (function | Some unif -> unif | _ -> raise Unif.Fail)
in
try
Unif.FO.matching ~subst ~pattern (t, sc)
with Unif.Fail ->
match T.view t with
| T.AppBuiltin(Builtin.Eq, ([_;a;b]|[a;b])) when tracking_eq () ->
begin try
Unif.FO.matching ~subst ~pattern (T.Form.eq b a, sc)
with Unif.Fail when decompose ->
try_decompositions a b end
| T.AppBuiltin(Builtin.Neq, ([_;a;b]|[a;b])) when tracking_eq () ->
Unif.FO.matching ~subst ~pattern (T.Form.neq b a, sc)
| _ -> raise Unif.Fail
let [@inline] flip_eq t =
match T.view t with
| T.AppBuiltin(Builtin.Eq, ([a;b]|[_;a;b])) when tracking_eq () ->
T.Form.eq b a
| T.AppBuiltin(Builtin.Neq, ([a;b]|[_;a;b])) when tracking_eq () ->
T.Form.neq b a
| _ -> t
let [@inline] cl_is_ht_trackable cl =
Trail.is_empty (C.trail cl) &&
(match C.lits cl with
| [| l1; l2 |] ->
CCOpt.is_some (get_predicate l1) && CCOpt.is_some (get_predicate l2)
| _ -> false)
let [@inline] rec normalize_negations lhs =
match T.view lhs with
| T.AppBuiltin(Builtin.Not, [t]) ->
(match T.view t with
| T.AppBuiltin(Builtin.Not, [s]) ->
normalize_negations s
| T.AppBuiltin(Builtin.Eq, ([_;a;b]|[a;b])) ->
T.Form.neq a b
| T.AppBuiltin(Builtin.Neq, ([_;a;b]|[a;b])) ->
T.Form.eq a b
| _ -> lhs)
| _ -> lhs
let [@inline] lit_to_term ?(negate=false) a_lhs sign =
let sign = if negate then not sign else sign in
normalize_negations (if sign then a_lhs else T.Form.not_ a_lhs)
let register_cl_term cl premise =
let premises, propagated =
Util.Int_map.get_or ~default:(Term.Set.empty, Term.Set.empty) (C.id cl) !cl_occs
in
cl_occs := Util.Int_map.add (C.id cl) ((Term.Set.add premise premises), propagated) !cl_occs
let register_cl_propagated cl premise =
let premises, propagated =
Util.Int_map.get_or ~default:(Term.Set.empty, Term.Set.empty) (C.id cl) !cl_occs
in
cl_occs := Util.Int_map.add (C.id cl) (premises, Term.Set.add premise propagated) !cl_occs
let register_propagated_lit ~prop_kind lit_t cl cs =
let has_renaming = ref false in
let to_remove = ref Term.Set.empty in
retrieve_idx ~getter:(PropagatedLitsIdx.retrieve_specializations (!propagated_, idx_sc)) (lit_t,q_sc)
|> Iter.iter (fun (t, _, subst) ->
if Subst.is_renaming subst then has_renaming := true
else (to_remove := Term.Set.add t !to_remove;)
);
if not @@ Term.Set.is_empty !to_remove then (
Util.debugf ~section 2 "removing: @[%a@]" (fun k -> k (Term.Set.pp T.pp) !to_remove));
Term.Set.iter (fun t ->
decr propagated_size_;
propagated_ :=
PropagatedLitsIdx.update_leaf !propagated_ t (fun _ -> false))
!to_remove;
if not (!propagated_size_ >= 0) then (
CCFormat.printf "prop size: %d@." !propagated_size_;
assert false
);
if not !has_renaming then (
let proofset = CS.add cl cs in
CS.iter (fun c -> register_cl_propagated c lit_t) proofset;
propagated_ := PropagatedLitsIdx.add !propagated_ lit_t (proofset, prop_kind);
incr propagated_size_
)
let react_unit_added unit_cl unit_term =
if should_update_propagated () then (
retrieve_idx ~getter:(PremiseIdx.retrieve_unifiables (!prems_, idx_sc)) (unit_term, q_sc)
|> Iter.iter (fun (_, (concls,_), subst) ->
let subst = Unif_subst.subst subst in
T.Tbl.to_iter concls
|> Iter.iter (fun (concl,cs) ->
let concl = Subst.FO.apply Subst.Renaming.none subst (concl, idx_sc) in
register_propagated_lit ~prop_kind:UnitPropagated concl unit_cl cs)))
let generalization_present premise concl =
retrieve_gen_prem_idx () (premise, q_sc)
|> Iter.exists (fun (_, (tbl, _), subst) ->
T.Tbl.keys tbl
|> Iter.exists (fun t ->
try
ignore(matching_eq ~subst ~pattern:(t, idx_sc) (concl, q_sc));
true
with Unif.Fail -> false))
let remove_instances premise concl =
retrieve_spec_prem_idx () (premise, q_sc)
|> (fun i -> Iter.fold (fun tasks (t, (tbl, _), subst) ->
let sets_to_remove =
Iter.fold (fun acc (s,cls) ->
try
let subst = matching_eq ~subst ~pattern:(concl,q_sc) (s,idx_sc) in
if Subst.is_renaming subst then acc else cls :: acc
with Unif.Fail -> acc
) [] (T.Tbl.to_iter tbl) in
if CCList.is_empty sets_to_remove then tasks
else (t, sets_to_remove) :: tasks
) [] i)
|> CCList.iter (fun (t, sets) ->
prems_ := PremiseIdx.update_leaf !prems_ t (fun (tbl, _) ->
T.Tbl.filter_map_inplace (fun concl proofset ->
if List.exists (fun set -> CS.subset set proofset) sets
then (concls_ := ConclusionIdx.remove !concls_ concl t; None)
else Some proofset) tbl;
T.Tbl.length tbl != 0
);
)
let compute_is_unit tbl concl cl =
let neg_concl = normalize_negations (T.Form.not_ concl) in
let neg_concl_flip = normalize_negations (T.Form.not_ (flip_eq concl)) in
T.Tbl.find_opt tbl neg_concl
|> CCOpt.(<+>) (T.Tbl.find_opt tbl neg_concl_flip)
|> CCOpt.(<$>) (CS.add cl)
let extend_concl premise concl cl =
Util.debugf ~section 3 "transitive conclusion: @[%a@] --> @[%a@]"
(fun k -> k T.pp premise T.pp concl);
let to_add_concl = ref [] in
let max_imps = Env.flex_get k_max_imp_entries in
retrieve_spec_concl_idx () (premise,q_sc)
|> Iter.iter (fun (concl',premise',subst) ->
prems_ := PremiseIdx.update_leaf !prems_ premise' (fun (tbl, is_unit) ->
(match T.Tbl.get tbl concl' with
| Some old_proofset ->
if CS.cardinal old_proofset < Env.flex_get k_max_depth then (
let concl = (Subst.FO.apply Subst.Renaming.none subst (concl, q_sc)) in
if not @@ T.Tbl.mem tbl concl && T.depth concl <= 4 && T.Tbl.length tbl <= max_imps then(
let proofset = CS.add cl old_proofset in
register_cl_term cl premise';
to_add_concl := (concl, premise', proofset, tbl) :: !to_add_concl))
| None -> assert false;);
true
));
CCList.iter (fun (c,premise,ps,tbl) ->
register_conclusion ~tbl ~premise c ps) !to_add_concl;
CCList.iter (fun (c,premise,ps,tbl) ->
match compute_is_unit tbl c cl with
| Some ps ->
prems_ := PremiseIdx.add !prems_ premise (tbl, true);
let neg_prem = normalize_negations (T.Form.not_ premise) in
register_propagated_lit ~prop_kind:Failed neg_prem cl ps
| _ -> ()
) !to_add_concl
let extend_premise tbl premise' concl cl =
let aux concl =
register_conclusion ~tbl ~premise:premise' concl (CS.singleton cl);
(match T.view concl with
| T.AppBuiltin(Builtin.Neq, ([_;a;b] | [a;b])) ->
iter_ctx a b
|> Iter.iter (fun (a,b) ->
let new_neq = T.Form.neq a b in
register_conclusion ~tbl ~premise:premise' new_neq (CS.singleton cl));
| _ -> ());
register_cl_term cl premise';
let max_proof_size = Env.flex_get k_max_depth in
retrieve_gen_prem_idx () (concl, q_sc)
|> Iter.iter (fun (_,(tbl', _),subst) ->
let to_add = ref [] in
T.Tbl.to_iter tbl'
|> Iter.iter (fun (t,proof_set) ->
if C.ClauseSet.cardinal proof_set < max_proof_size then (
let concl = (Subst.FO.apply Subst.Renaming.none subst (t, idx_sc)) in
if T.depth concl <= 4 then (
let new_cls = CS.add cl proof_set in
CS.iter (fun cl -> register_cl_term cl premise') new_cls;
to_add := (concl, new_cls) :: !to_add);
));
CCList.iter (fun (c,n) ->
register_conclusion ~tbl ~premise:premise' c n) !to_add
) in
try
let subst = Unif.FO.matching ~pattern:(premise',0) (concl,1) in
let i = ref 0 in
let concl' = Subst.FO.apply Subst.Renaming.none subst (concl,0) in
if T.equal concl concl' then raise Unif.Fail;
let concl = ref concl in
while !i <= Env.flex_get k_max_self_impls do
aux !concl;
concl := Subst.FO.apply Subst.Renaming.none subst (!concl,0);
if T.depth !concl > 3 then (
i := Env.flex_get k_max_self_impls + 1
);
i := !i + 1;
done;
with Unif.Fail ->
aux concl
let get_unit_predicate cl =
if Trail.is_empty (C.trail cl) then (
match C.lits cl with
| [| (L.Equation(lhs, _, _) as l) |] when L.is_predicate_lit l ->
Some (lit_to_term lhs (L.is_positivoid l))
| [| L.Equation(lhs, rhs, sign) |] when tracking_eq () ->
Some (lit_to_term (T.Form.eq lhs rhs) (sign))
| _ -> None)
else None
let add_new_premise premise concl cl =
let alpha_renaming =
retrieve_spec_prem_idx () (premise, q_sc)
|> Iter.find (fun (premise', tbl, subst) ->
if Subst.is_renaming subst then Some (premise', subst)
else None
) in
match alpha_renaming with
| Some (premise', subst) ->
let concl = Subst.FO.apply Subst.Renaming.none subst (concl, q_sc) in
let became_unit = ref None in
prems_ := PremiseIdx.update_leaf !prems_ premise' (fun (tbl,is_unit) ->
if not (T.Tbl.mem tbl concl) && not (T.Tbl.mem tbl (flip_eq concl)) &&
T.Tbl.length tbl <= Env.flex_get k_max_imp_entries then (
extend_premise tbl premise' concl cl;
if not is_unit then (
(match compute_is_unit tbl concl cl with
| Some ps -> became_unit := Some (ps, tbl)
| None -> ());
)
);
CCOpt.is_none !became_unit
);
(match !became_unit with
| Some (ps,tbl) ->
ignore(PremiseIdx.update_leaf !prems_ premise' (fun (tbl, is_unit) -> assert false));
prems_ := PremiseIdx.add !prems_ premise' (tbl,true);
let neg_prem = normalize_negations (T.Form.not_ premise') in
register_propagated_lit ~prop_kind:Failed neg_prem cl ps
| None -> ())
| _ ->
let tbl = T.Tbl.create 64 in
extend_premise tbl premise concl cl;
match compute_is_unit tbl concl cl with
| Some ps ->
prems_ := PremiseIdx.add !prems_ premise (tbl,true);
let neg_prem = normalize_negations (T.Form.not_ premise) in
register_propagated_lit ~prop_kind:Failed neg_prem cl ps
| None -> prems_ := PremiseIdx.add !prems_ premise (tbl,false)
let normalize_variables premise concl =
let to_rename = T.VarSet.diff (T.vars concl) (T.vars premise) in
if T.VarSet.is_empty to_rename then premise,concl
else (
let renamer = T.VarSet.fold (fun var subst ->
let ty = HVar.ty var in
Subst.FO.bind' subst (var, 0) (T.var (HVar.fresh ~ty ()), 0)
) to_rename Subst.empty in
premise, Subst.FO.apply Subst.Renaming.none renamer (concl,0)
)
let max_t_depth = 3
let insert_implication premise concl cl =
if T.depth premise <= max_t_depth && T.depth concl <= max_t_depth &&
not (T.equal premise concl) &&
not (T.equal premise (flip_eq concl) &&
not (generalization_present premise concl)) then (
Util.debugf ~section 3 "inserting @[%a@] -> @[%a@]" (fun k -> k T.pp premise T.pp concl);
let premise, concl = normalize_variables premise concl in
remove_instances premise concl;
extend_concl premise concl cl;
add_new_premise premise concl cl;
)
let insert_into_indices cl =
match CCArray.map get_predicate (C.lits cl) with
| [| Some (a_lhs, a_sign); Some (b_lhs, b_sign) |] ->
let elig =
if Env.flex_get k_insert_only_ordered
then C.eligible_param (cl,0) Subst.empty
else CCBV.create ~size:2 true in
if (CCBV.get elig 0) then (
insert_implication (lit_to_term ~negate:true a_lhs a_sign)
(lit_to_term b_lhs b_sign) cl);
if (CCBV.get elig 1) then (
insert_implication (lit_to_term ~negate:true b_lhs b_sign)
(lit_to_term a_lhs a_sign) cl)
| _ -> ()
let can_track_bin_cl cl =
cl_is_ht_trackable cl &&
(Env.flex_get k_max_tracked_clauses == -1 ||
!tracked_binary <= Env.flex_get k_max_tracked_clauses)
let can_track_unary_cl cl =
Env.flex_get k_unit_propagated_hle &&
(Env.flex_get k_max_tracked_clauses == -1 ||
!tracked_unary <= 4*Env.flex_get k_max_tracked_clauses)
let steps = ref 0
let track_clause cl =
try
if Env.flex_get k_heartbeat_disabled_hlbe then raise RuleNotApplicable;
(match Env.flex_get k_heartbeat_steps with
| Some h_steps when !steps!=0 && !steps mod h_steps = 0 ->
if !heartbeat_ then heartbeat_ := false
else (
CCFormat.printf "disabling heartbeat %d@." !steps;
Env.flex_add k_heartbeat_disabled_hlbe true;
raise RuleNotApplicable;
)
| _ -> ());
if can_track_bin_cl cl then (
Util.debugf ~section 2 "tracking @[%a@]" (fun k -> k C.pp cl);
insert_into_indices cl;
incr tracked_binary;
) else if can_track_unary_cl cl then (
match get_unit_predicate cl with
| Some unit ->
react_unit_added cl unit;
incr tracked_unary
| None -> ());
with RuleNotApplicable -> ()
let make_tauto ~proof =
C.create ~penalty:1 ~trail:Trail.empty [Literal.mk_tauto] proof
let penalize_hidden_tautology cl =
if Env.flex_get k_penalize_tautologies &&
not @@ ID.Set.exists (fun id -> Signature.sym_in_conj id (Env.signature ()))
(C.symbols (Iter.singleton cl))
then (C.inc_penalty cl (C.length cl - 1))
let find_implication cl premise concl =
retrieve_gen_prem_idx () (premise, q_sc)
|> Iter.find (fun (premise', (tbl,_), subst) ->
T.Tbl.to_iter tbl
|> Iter.find (fun (concl', proofset) ->
try
if CS.mem cl proofset then None
else (
let subst = matching_eq ~decompose:true ~subst ~pattern:(concl', idx_sc) (concl, q_sc) in
Some(premise', concl', proofset, subst))
with Unif.Fail -> None))
let do_unit_hle_htr cl =
let n = C.length cl in
let bv = CCBV.create ~size:n true in
let exception UnitHTR of int * (CS.t * propagation_kind) in
let proofset = ref CS.empty in
try
if Env.flex_get k_heartbeat_disabled_hlbe then raise RuleNotApplicable;
if n>7 then raise RuleNotApplicable;
CCArray.iteri (fun i lit ->
match get_predicate lit with
| Some (i_lhs, i_sign) ->
let i_t = lit_to_term (i_lhs) (i_sign) in
let i_neg_t = lit_to_term ~negate:true (i_lhs) (i_sign) in
if n!=1 && Env.flex_get k_reduce_tautologies then (
retrieve_idx ~getter:(PropagatedLitsIdx.retrieve_generalizations (!propagated_, idx_sc))
(i_t, q_sc)
|> Iter.head
|> CCOpt.iter (fun (_,ps,_) -> raise (UnitHTR(i,ps))));
if Env.flex_get k_delete_lits then (
retrieve_idx ~getter:(PropagatedLitsIdx.retrieve_generalizations (!propagated_, idx_sc)) (i_neg_t, q_sc)
|> Iter.head
|> CCOpt.iter (fun (_,(ps, _),_) ->
proofset := CS.union ps !proofset;
CCBV.reset bv i))
| None -> ()
) (C.lits cl);
if CCBV.is_empty (CCBV.negate bv) then None
else (
let lit_l = List.rev @@ CCBV.select bv (C.lits cl) in
let proof =
Proof.Step.simp ~rule:(Proof.Rule.mk "unit_hle/fle")
(List.map C.proof_parent (cl :: CS.to_list !proofset))
in
let res = C.create ~penalty:(C.penalty cl) ~trail:(C.trail cl) lit_l proof in
Util.debugf ~section 2 "simplified[fle]: @[%a@] --> @[%a@]"
(fun k -> k C.pp cl C.pp res);
Util.debugf ~section 2 "used: @[%a@]" (fun k -> k (CS.pp C.pp) !proofset);
Some (res))
with UnitHTR(idx, (ps, prop_kind)) ->
let lit_l = [CCArray.get (C.lits cl) idx] in
let proof =
Proof.Step.simp ~rule:(Proof.Rule.mk (if prop_kind = Failed then "ftr" else "unit_htr"))
(List.map C.proof_parent (cl :: CS.to_list ps))
in
let repl = C.create ~penalty:(C.penalty cl) ~trail:(C.trail cl) lit_l proof in
penalize_hidden_tautology repl;
Util.debugf ~section 2 "simplified[unit_htr]: @[@[%a@] --> @[%a@]@]"
(fun k -> k C.pp cl C.pp repl);
Some (repl)
| RuleNotApplicable -> None
let do_hte_hle cl =
let exception HiddenTauto of int * int * CS.t in
let n = C.length cl in
try
if Env.flex_get k_heartbeat_disabled_hlbe then raise RuleNotApplicable;
if n > 7 then raise RuleNotApplicable;
let bv = CCBV.create ~size:n true in
let (<+>) = CCOpt.(<+>) in
let proofset = ref CS.empty in
CCArray.iteri (fun i i_lit ->
match get_predicate i_lit with
| Some(i_lhs, i_sign) when CCBV.get bv i ->
let i_t = lit_to_term (i_lhs) (i_sign) in
let i_neg_t = lit_to_term ~negate:true (i_lhs) (i_sign) in
CCArray.iteri (fun j j_lit ->
begin match get_predicate j_lit with
| Some (j_lhs, j_sign) when CCBV.get bv j && i!=j ->
let j_t = lit_to_term (j_lhs) (j_sign) in
let j_neg_t = lit_to_term ~negate:true (j_lhs) (j_sign) in
if Env.flex_get k_reduce_tautologies && C.length cl != 2 then (
(match find_implication cl i_neg_t j_t
<+> find_implication cl j_neg_t i_t with
| Some (lit_a, lit_b, proofset, subst)
when (not (CS.mem cl proofset)) &&
(C.length cl != 2 || not (Subst.is_renaming subst)) ->
raise (HiddenTauto (i, j, proofset))
| _ -> ())
);
if Env.flex_get k_delete_lits then (
(match find_implication cl i_neg_t j_neg_t
<+> find_implication cl j_t i_t with
| Some (_, _, proofset',subst) ->
CCBV.reset bv j;
Util.debugf ~section 3 "@[%a@] --> @[%a@]"
(fun k -> k T.pp i_neg_t T.pp j_neg_t);
Util.debugf ~section 3 "used(%d): @[%a@]"
(fun k -> k j (CS.pp C.pp) proofset');
proofset := CS.union proofset' !proofset
| _ -> () )
)
| _ -> () end
) (C.lits cl)
| _ -> ()
) (C.lits cl);
if CCBV.is_empty (CCBV.negate bv) then None
else (
let lit_l = List.rev @@ CCBV.select bv (C.lits cl) in
let proof =
Proof.Step.simp ~rule:(Proof.Rule.mk "hidden_literal_elimination")
(List.map C.proof_parent (cl :: CS.to_list !proofset))
in
let res = C.create ~penalty:(C.penalty cl) ~trail:(C.trail cl) lit_l proof in
Util.debugf ~section 2 "simplified[hle]: @[%a@] --> @[%a@]"
(fun k -> k C.pp cl C.pp res);
Util.debugf ~section 2 "used: @[%a@]" (fun k -> k (CS.pp C.pp) !proofset);
Some (res))
with HiddenTauto(i,j,proofset) ->
let lit_l = [CCArray.get (C.lits cl) i; CCArray.get (C.lits cl) j] in
let proof =
Proof.Step.simp ~rule:(Proof.Rule.mk "hidden_tautology_elimination")
(List.map C.proof_parent (cl :: CS.to_list proofset))
in
let repl = C.create ~penalty:(C.penalty cl) ~trail:(C.trail cl) lit_l proof in
penalize_hidden_tautology repl;
Some repl
|> CCFun.tap (function
| Some res ->
Util.debugf ~section 2 "HTR(@[%a@])=@[%a@]@. > @[%a@]"
(fun k -> k C.pp cl C.pp res (CS.pp C.pp) proofset);
| _ -> ())
| RuleNotApplicable -> None
let do_context_simplification cl =
let lits_to_keep = CCBV.create ~size:(C.length cl) true in
let exception StopIteration in
CCArray.iteri (fun i lit ->
if CCBV.get lits_to_keep i && not (Lit.is_predicate_lit lit) then (
try
CCArray.iteri (fun j lit' ->
if i!=j && CCBV.get lits_to_keep j && not (Lit.is_predicate_lit lit')
&& Lit.is_positivoid lit = Lit.is_positivoid lit' then (
match Lit.View.as_eqn lit, Lit.View.as_eqn lit' with
| Some(s,t,sign), Some(ctx_s, ctx_t, _) ->
iter_ctx ctx_s ctx_t (fun (s',t') ->
if (T.equal s s' && T.equal t t') ||
(T.equal s t' && T.equal t s') then (
if sign then (
CCBV.reset lits_to_keep i;
raise StopIteration;
) else (CCBV.reset lits_to_keep j)
))
| _ -> ()
)) (C.lits cl);
with StopIteration -> ()
)) (C.lits cl);
if CCBV.is_empty (CCBV.negate lits_to_keep) then None
else (
let lit_l = List.rev @@ CCBV.select lits_to_keep (C.lits cl) in
let proof =
Proof.Step.simp
~rule:(Proof.Rule.mk "eq_context_simplification")
([C.proof_parent cl])
in
let res = C.create ~penalty:(C.penalty cl) ~trail:(C.trail cl) lit_l proof in
Some (res))
let simplify_opt ~f cl =
if is_tauto cl then (SimplM.return_same cl)
else (match f cl with
| Some cl' -> SimplM.return_new cl'
| None -> SimplM.return_same cl)
let [@inline] check_heartbeat arg =
if CCOpt.is_some arg then heartbeat_ := true;
arg
let hle_htr = simplify_opt ~f:(fun a -> check_heartbeat @@ do_hte_hle a)
let unit_hle_htr = simplify_opt ~f:(fun a -> check_heartbeat @@ do_unit_hle_htr a)
let ctx_simpl = simplify_opt ~f:do_context_simplification
let untrack_clause cl =
(match Util.Int_map.get (C.id cl) !cl_occs with
| Some (premises, propagated) ->
Term.Set.iter (fun premise ->
prems_ := PremiseIdx.update_leaf !prems_ premise (fun (tbl,_) ->
T.Tbl.filter_map_inplace (fun concl proofset ->
if CS.mem cl proofset then (
concls_ := ConclusionIdx.remove !concls_ concl premise;
None
) else Some proofset) tbl;
T.Tbl.length tbl != 0)) premises;
Term.Set.iter (fun prop_lit ->
propagated_ := PropagatedLitsIdx.update_leaf !propagated_ prop_lit (fun (cs, _) ->
if (not @@ CS.mem cl cs) then (decr propagated_size_; false) else true
)
) propagated
| _ -> ());
if Util.Int_map.mem (C.id cl) !cl_occs then (
Util.debugf ~section 3 "removed: @[%a@]." (fun k -> k C.pp cl);
decr tracked_binary;
);
cl_occs := Util.Int_map.remove (C.id cl) !cl_occs;
match get_unit_predicate cl with
| Some unit ->
units_ := UnitIdx.remove !units_ unit cl;
decr tracked_unary;
| None -> ()
let initialize () =
let track_active () =
Signal.on_every Env.ProofState.ActiveSet.on_add_clause track_clause;
Signal.on_every Env.ProofState.ActiveSet.on_remove_clause untrack_clause;
Signal.on_every Env.on_forward_simplified (fun (_, _) -> incr steps);
in
let track_passive () =
Signal.on_every Env.ProofState.PassiveSet.on_add_clause track_clause;
Signal.on_every Env.ProofState.PassiveSet.on_remove_clause untrack_clause;
Signal.on_every Env.on_forward_simplified (fun (_, _) -> incr steps)
in
let track_all () =
Signal.on_every Env.ProofState.PassiveSet.on_add_clause track_clause;
Signal.on_every Env.ProofState.ActiveSet.on_remove_clause untrack_clause;
Signal.on_every Env.on_forward_simplified (fun (c, new_state) ->
incr steps;
match new_state with
| Some c' ->
if not (C.equal c c') then (
untrack_clause c;
track_clause c'
)
| _ -> untrack_clause c )
in
let initialize_with_passive () =
Iter.iter track_clause (E.get_passive ());
Util.debugf ~section 3 "discovered implications:" CCFun.id;
PremiseIdx.iter !prems_ (fun premise (tbl,_) ->
Util.debugf ~section 3 "@[%a@] --> @[%a@]" (fun k -> k T.pp premise (Iter.pp_seq T.pp) (T.Tbl.keys tbl))
)
in
begin match Env.flex_get k_clauses_to_track with
| `Passive ->
initialize_with_passive ();
track_passive ()
| `Active ->
track_active ()
| `All ->
initialize_with_passive ();
track_all ()
end;
Signal.StopListening
let setup () =
if E.flex_get k_enabled then (
Signal.on Env.on_start initialize;
let add_simpl =
if Env.flex_get k_simpl_new
then Env.add_basic_simplify
else Env.add_active_simplify
in
if Env.flex_get k_basic_rules then add_simpl hle_htr;
add_simpl ctx_simpl;
if Env.flex_get k_unit_propagated_hle then (add_simpl unit_hle_htr);
)
end
let max_depth_ = ref 3
let enabled_ = ref false
let simpl_new_ = ref false
let clauses_to_track_ = ref `Active
let max_self_impls_ = ref 1
let max_tracked_clauses = ref (-1)
let propagated_hle = ref true
let hte_ = ref true
let hle_ = ref true
let track_eq_ = ref false
let insert_ordered_ = ref false
let heartbeat_steps = ref None
let max_imp_ = ref 48
let basic_rules_ = ref true
let penalize_tautologies_ = ref true
let extension =
let register env =
let module E = (val env : Env.S) in
let module HLT = Make(E) in
E.flex_add k_enabled !enabled_;
E.flex_add k_max_depth !max_depth_;
E.flex_add k_simpl_new !simpl_new_;
E.flex_add k_clauses_to_track !clauses_to_track_;
E.flex_add k_max_self_impls !max_self_impls_;
E.flex_add k_unit_propagated_hle !propagated_hle;
E.flex_add k_max_tracked_clauses !max_tracked_clauses;
E.flex_add k_track_eq !track_eq_;
E.flex_add k_delete_lits !hle_;
E.flex_add k_reduce_tautologies !hte_;
E.flex_add k_insert_only_ordered !insert_ordered_;
E.flex_add k_heartbeat_steps !heartbeat_steps;
E.flex_add k_heartbeat_disabled_hlbe false;
E.flex_add k_max_imp_entries !max_imp_;
E.flex_add k_basic_rules !basic_rules_;
E.flex_add k_penalize_tautologies !penalize_tautologies_;
HLT.setup ()
in
{ Extensions.default with
Extensions.name = "hidden literal elimination";
prio = 45;
env_actions=[register]
}
let () =
Options.add_opts [
"--hlbe-elim", Arg.Bool ((:=) enabled_), " enable/disable hidden literal and tautology elimination";
"--hlbe-elim-max-tracked", Arg.Int ((:=) max_tracked_clauses), " negative value for disabling the limit";
"--hlbe-elim-lits", Arg.Bool ((:=) hle_), " remove literals using HLBE (hidden-lt-elim must be on)";
"--hlbe-reduce-tautologies", Arg.Bool ((:=) hte_), " reduce tautologies using HLBE (hidden-lt-elim must be on)";
"--hlbe-max-depth", Arg.Set_int max_depth_, " max depth of binary implication graph precomputation";
"--hlbe-simplify-new", Arg.Bool ((:=) simpl_new_), " apply HLTe also when moving a clause from fresh to passive";
"--hlbe-track-eq", Arg.Bool ((:=) track_eq_), " enable/disable tracking and simplifying equality literals";
"--hlbe-heartbeat", Arg.Int (fun v -> heartbeat_steps := Some v),
" when set to n, every n steps it will be checked if any HLBE simplification is performed." ^
" If not, any HLBE will be disabled.";
"--hlbe-clauses-to-track", Arg.Symbol(["all";"passive";"active"],
(function
| "all" ->
clauses_to_track_ := `All;
| "passive" ->
clauses_to_track_ := `Passive;
| "active" ->
clauses_to_track_ := `Active;
| _ -> ())),
" what clauses to use for simplification";
"--hlbe-max-self-implications", Arg.Int ((:=) max_self_impls_),
" how many times do we loop implications of the kind p(X) -> p(f(X)) ";
"--hlbe-unit-rules", Arg.Bool ((:=) propagated_hle),
" do unit-triggered removal of literals ";
"--hlbe-insert-ordered", Arg.Bool ((:=) insert_ordered_),
" for clauses of the form l|r where l > r then insert only ~l -> r ";
"--hlbe-max-entries", Arg.Int ((:=) max_imp_),
" maximal number of entries stored for each element mapped by implication map ";
"--hlbe-basic-rules", Arg.Bool ((:=) basic_rules_), " enable/disable basic (non unit) rules HLE and HTR";
"--hlbe-penalize-tautologies", Arg.Bool ((:=) penalize_tautologies_), " penalize hidden tautologies"
];
Extensions.register extension