exception Success of B.t Terms.bag * int * B.t Terms.unit_clause
- let debug s =
- () (* prerr_endline s *)
- ;;
+ let debug s = prerr_endline s;;
+ let debug _ = ();;
let rec list_first f = function
| [] -> None
let newside = Subst.apply_subst subst newside in
let o = Order.compare_terms newside side in
(* Riazanov, pp. 45 (ii) *)
- if o = Terms.Lt then
+ if o = Terms.Lt then
Some (context newside, subst, varlist, id, pos, dir)
else
((*prerr_endline ("Filtering: " ^
(IDX.ClauseSet.elements cands)
;;
- (* XXX: possible optimization, if the literal has a "side" already
- * in normal form we should not traverse it again *)
- let demodulate_once bag (id, literal, vl, pr) table =
+ let demodulate_once ~jump_to_right bag (id, literal, vl, pr) table =
(* debug ("Demodulating : " ^ (Pp.pp_unit_clause (id, literal, vl, pr)));*)
match literal with
| Terms.Predicate t -> assert false
| Terms.Equation (l,r,ty,_) ->
- match first_position [2]
- (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; x; r ]) l
- (demod table vl)
- with
+ let left_position = if jump_to_right then None else
+ first_position [2]
+ (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; x; r ]) l
+ (demod table vl)
+ in
+ match left_position with
| Some (newt, subst, varlist, id2, pos, dir) ->
- build_clause bag (fun _ -> true) Terms.Demodulation
- newt subst varlist id id2 pos dir
+ begin
+ match build_clause bag (fun _ -> true) Terms.Demodulation
+ newt subst varlist id id2 pos dir
+ with
+ | None -> assert false
+ | Some x -> Some (x,false)
+ end
| None ->
match first_position
[3] (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; l; x ]) r
with
| None -> None
| Some (newt, subst, varlist, id2, pos, dir) ->
- build_clause bag (fun _ -> true) Terms.Demodulation
- newt subst varlist id id2 pos dir
+ match build_clause bag (fun _ -> true)
+ Terms.Demodulation newt subst varlist id id2 pos dir
+ with
+ | None -> assert false
+ | Some x -> Some (x,true)
;;
- let rec demodulate bag clause table =
- match demodulate_once bag clause table with
+ let rec demodulate ~jump_to_right bag clause table =
+ match demodulate_once ~jump_to_right bag clause table with
| None -> bag, clause
- | Some (bag, clause) -> demodulate bag clause table
+ | Some ((bag, clause),r) -> demodulate ~jump_to_right:r
+ bag clause table
+ ;;
+
+ let demodulate bag clause table = demodulate ~jump_to_right:false
+ bag clause table
;;
(* move away *)
- let is_identity_clause = function
+ let is_identity_clause ~unify = function
| _, Terms.Equation (_,_,_,Terms.Eq), _, _ -> true
- | _, Terms.Predicate _, _, _ -> assert false
- | _ -> false
+ | _, Terms.Equation (l,r,_,_), vl, proof when unify ->
+ (try ignore(Unif.unification vl [] l r); true
+ with FoUnif.UnificationFailure _ -> false)
+ | _, Terms.Equation (_,_,_,_), _, _ -> false
+ | _, Terms.Predicate _, _, _ -> assert false
;;
let build_new_clause bag maxvar filter rule t subst vl id id2 pos dir =
| None -> None
;;
-
let fold_build_new_clause bag maxvar id rule filter res =
let (bag, maxvar), res =
HExtlib.filter_map_acc
bag, maxvar, res
;;
+
+ let rewrite_eq ~unify l r ty vl table =
+ let retrieve = if unify then IDX.DT.retrieve_unifiables
+ else IDX.DT.retrieve_generalizations in
+ let lcands = retrieve table l in
+ let rcands = retrieve table r in
+ let f b c =
+ let id, dir, l, r, vl =
+ match c with
+ | (d, (id,Terms.Equation (l,r,ty,_),vl,_))-> id, d, l, r, vl
+ |_ -> assert false
+ in
+ let reverse = (dir = Terms.Left2Right) = b in
+ let l, r, proof_rewrite_dir = if reverse then l,r,Terms.Left2Right
+ else r,l, Terms.Right2Left in
+ (id,proof_rewrite_dir,Terms.Node [ Terms.Leaf B.eqP; ty; l; r ], vl)
+ in
+ let cands1 = List.map (f true) (IDX.ClauseSet.elements lcands) in
+ let cands2 = List.map (f false) (IDX.ClauseSet.elements rcands) in
+ let t = Terms.Node [ Terms.Leaf B.eqP; ty; l; r ] in
+ let locked_vars = if unify then [] else vl in
+ let rec aux = function
+ | [] -> None
+ | (id2,dir,c,vl1)::tl ->
+ try
+ let subst,vl1 = Unif.unification (vl@vl1) locked_vars c t in
+ Some (id2, dir, subst)
+ with FoUnif.UnificationFailure _ -> aux tl
+ in
+ aux (cands1 @ cands2)
+ ;;
+
let is_subsumed ~unify bag maxvar (id, lit, vl, _) table =
match lit with
| Terms.Predicate _ -> assert false
| Terms.Equation (l,r,ty,_) ->
- let retrieve = if unify then IDX.DT.retrieve_unifiables
- else IDX.DT.retrieve_generalizations in
- let lcands = retrieve table l in
- let rcands = retrieve table r in
- let f b c =
- let id, dir, l, r, vl =
- match c with
- | (d, (id,Terms.Equation (l,r,ty,_),vl,_))-> id, d, l, r, vl
- |_ -> assert false
- in
- let reverse = (dir = Terms.Left2Right) = b in
- let l, r, proof_rewrite_dir = if reverse then l,r,Terms.Left2Right
- else r,l, Terms.Right2Left in
- (id,proof_rewrite_dir,Terms.Node [ Terms.Leaf B.eqP; ty; l; r ], vl)
- in
- let cands1 = List.map (f true) (IDX.ClauseSet.elements lcands) in
- let cands2 = List.map (f false) (IDX.ClauseSet.elements rcands) in
- let t = Terms.Node [ Terms.Leaf B.eqP; ty; l; r ] in
- let locked_vars = if unify then [] else vl in
- let rec aux = function
- | [] -> None
- | (id2,dir,c,vl1)::tl ->
- try
- let subst,vl1 = Unif.unification (vl@vl1) locked_vars c t in
- let id_t = Terms.Node [ Terms.Leaf B.eqP; ty; r; r ] in
- build_new_clause bag maxvar (fun _ -> true)
- Terms.Superposition id_t subst [] id id2 [2] dir
- with FoUnif.UnificationFailure _ -> aux tl
- in
- aux (cands1 @ cands2)
+ match rewrite_eq ~unify l r ty vl table with
+ | None -> None
+ | Some (id2, dir, subst) ->
+ let id_t = Terms.Node [ Terms.Leaf B.eqP; ty; r; r ] in
+ build_new_clause bag maxvar (fun _ -> true)
+ Terms.Superposition id_t subst [] id id2 [2] dir
+ ;;
+ (* id refers to a clause proving contextl l = contextr r *)
+
+ let rec deep_eq ~unify l r ty pos contextl contextr table acc =
+ match acc with
+ | None -> None
+ | Some(bag,maxvar,(id,lit,vl,p),subst) ->
+ let l = Subst.apply_subst subst l in
+ let r = Subst.apply_subst subst r in
+ try
+ let subst1,vl1 = Unif.unification vl [] l r in
+ let lit =
+ match lit with Terms.Predicate _ -> assert false
+ | Terms.Equation (l,r,ty,o) ->
+ Terms.Equation (FoSubst.apply_subst subst1 l,
+ FoSubst.apply_subst subst1 r, ty, o)
+ in
+ Some(bag,maxvar,(id,lit,vl1,p),Subst.concat subst1 subst)
+ with FoUnif.UnificationFailure _ ->
+ match rewrite_eq ~unify l r ty vl table with
+ | Some (id2, dir, subst1) ->
+ let newsubst = Subst.concat subst1 subst in
+ let id_t =
+ FoSubst.apply_subst newsubst
+ (Terms.Node[Terms.Leaf B.eqP;ty;contextl r;contextr r])
+ in
+ (match
+ build_new_clause bag maxvar (fun _ -> true)
+ Terms.Superposition id_t
+ subst1 [] id id2 (pos@[2]) dir
+ with
+ | Some ((bag, maxvar), c) ->
+ Some(bag,maxvar,c,newsubst)
+ | None -> assert false)
+ | None ->
+ match l,r with
+ | Terms.Node (a::la), Terms.Node (b::lb) when
+ a = b && List.length la = List.length lb ->
+ let acc,_,_,_ =
+ List.fold_left2
+ (fun (acc,pre,postl,postr) a b ->
+ let newcl =
+ fun x -> contextl(Terms.Node (pre@(x::postl))) in
+ let newcr =
+ fun x -> contextr(Terms.Node (pre@(x::postr))) in
+ let newpos = List.length pre::pos in
+ let footail l =
+ if l = [] then [] else List.tl l in
+ (deep_eq ~unify a b ty
+ newpos newcl newcr table acc,pre@[b],
+ footail postl, footail postr))
+ (acc,[a],List.tl la,List.tl lb) la lb
+ in acc
+ | _,_ -> None
+ ;;
+
+ let rec orphan_murder bag acc i =
+ match Terms.M.find i bag with
+ | (_,_,_,Terms.Exact _),discarded -> (discarded,acc)
+ | (_,_,_,Terms.Step (_,i1,i2,_,_,_)),true -> (true,acc)
+ | (_,_,_,Terms.Step (_,i1,i2,_,_,_)),false ->
+ if (List.mem i acc) then (false,acc)
+ else match orphan_murder bag acc i1 with
+ | (true,acc) -> (true,acc)
+ | (false,acc) ->
+ let (res,acc) = orphan_murder bag acc i2 in
+ if res then res,acc else res,i::acc
+ ;;
+
+ let orphan_murder bag actives cl =
+ let (id,_,_,_) = cl in
+ let actives = List.map (fun (i,_,_,_) -> i) actives in
+ let (res,_) = orphan_murder bag actives id in
+ if res then debug "Orphan murdered"; res
;;
(* demodulate and check for subsumption *)
let simplify table maxvar bag clause =
- let bag, clause = demodulate bag clause table in
- if is_identity_clause clause then None
+ if is_identity_clause ~unify:false clause then bag,None
+ (* else if orphan_murder bag actives clause then bag,None *)
+ else let bag, clause = demodulate bag clause table in
+ if is_identity_clause ~unify:false clause then bag,None
else
match is_subsumed ~unify:false bag maxvar clause table with
- | None -> Some (bag, clause)
- | Some _ -> None
+ | None -> bag, Some clause
+ | Some _ -> bag, None
+ ;;
+
+ let simplify table maxvar bag clause =
+ match simplify table maxvar bag clause with
+ | bag, None -> let (id,_,_,_) = clause in
+ Terms.M.add id (clause,true) bag, None
+ | bag, Some clause -> bag, Some clause
+ (*let (id,_,_,_) = clause in
+ if orphan_murder bag clause then
+ Terms.M.add id (clause,true) bag, Some clause
+ else bag, Some clause*)
;;
let one_pass_simplification new_clause (alist,atable) bag maxvar =
match simplify atable maxvar bag new_clause with
- | None -> None (* new_clause has been discarded *)
- | Some (bag, clause) ->
+ | bag,None -> bag,None (* new_clause has been discarded *)
+ | bag,(Some clause) ->
let ctable = IDX.index_unit_clause IDX.DT.empty clause in
let bag, alist, atable =
List.fold_left
- (fun (bag, alist, atable as acc) c ->
+ (fun (bag, alist, atable) c ->
match simplify ctable maxvar bag c with
- |None -> acc (* an active clause as been discarded *)
- |Some (bag, c1) ->
+ |bag,None -> (bag,alist,atable)
+ (* an active clause as been discarded *)
+ |bag,Some c1 ->
bag, c :: alist, IDX.index_unit_clause atable c)
(bag,[],IDX.DT.empty) alist
in
- Some (clause, bag, (alist,atable))
+ bag, Some (clause, (alist,atable))
;;
let simplification_step ~new_cl cl (alist,atable) bag maxvar new_clause =
(* Simplification of new_clause with : *
* - actives and cl if new_clause is not cl *
* - only actives otherwise *)
- match simplify atable1 maxvar bag new_clause with
- | None -> (Some cl, None) (* new_clause has been discarded *)
- | Some (bag, clause) ->
+ match
+ simplify atable1 maxvar bag new_clause with
+ | bag,None -> bag,(Some cl, None) (* new_clause has been discarded *)
+ | bag,Some clause ->
(* Simplification of each active clause with clause *
* which is the simplified form of new_clause *)
let ctable = IDX.index_unit_clause IDX.DT.empty clause in
let bag, newa, alist, atable =
List.fold_left
- (fun (bag, newa, alist, atable as acc) c ->
+ (fun (bag, newa, alist, atable) c ->
match simplify ctable maxvar bag c with
- |None -> acc (* an active clause as been discarded *)
- |Some (bag, c1) ->
+ |bag,None -> (bag, newa, alist, atable)
+ (* an active clause as been discarded *)
+ |bag,Some c1 ->
if (c1 == c) then
bag, newa, c :: alist,
IDX.index_unit_clause atable c
(bag,[],[],IDX.DT.empty) alist
in
if new_cl then
- (Some cl, Some (clause, (alist,atable), newa, bag))
+ bag, (Some cl, Some (clause, (alist,atable), newa))
else
(* if new_clause is not cl, we simplify cl with clause *)
match simplify ctable maxvar bag cl with
- | None ->
+ | bag,None ->
(* cl has been discarded *)
- (None, Some (clause, (alist,atable), newa, bag))
- | Some (bag,cl1) ->
- (Some cl1, Some (clause, (alist,atable), newa, bag))
+ bag,(None, Some (clause, (alist,atable), newa))
+ | bag,Some cl1 ->
+ bag,(Some cl1, Some (clause, (alist,atable), newa))
;;
let keep_simplified cl (alist,atable) bag maxvar =
let rec keep_simplified_aux ~new_cl cl (alist,atable) bag newc =
if new_cl then
match simplification_step ~new_cl cl (alist,atable) bag maxvar cl with
- | (None, _) -> assert false
- | (Some _, None) -> None
- | (Some _, Some (clause, (alist,atable), newa, bag)) ->
+ | _,(None, _) -> assert false
+ | bag,(Some _, None) -> bag,None
+ | bag,(Some _, Some (clause, (alist,atable), newa)) ->
keep_simplified_aux ~new_cl:(cl!=clause) clause (alist,atable)
bag (newa@newc)
else
match newc with
- | [] -> Some (cl, bag, (alist,atable))
+ | [] -> bag, Some (cl, (alist,atable))
| hd::tl ->
match simplification_step ~new_cl cl
(alist,atable) bag maxvar hd with
- | (None,None) -> assert false
- | (Some _,None) ->
+ | _,(None,None) -> assert false
+ | bag,(Some _,None) ->
keep_simplified_aux ~new_cl cl (alist,atable) bag tl
- | (None, Some _) -> None
- | (Some cl1, Some (clause, (alist,atable), newa, bag)) ->
+ | bag,(None, Some _) -> bag,None
+ | bag,(Some cl1, Some (clause, (alist,atable), newa)) ->
let alist,atable =
(clause::alist, IDX.index_unit_clause atable clause)
in
bag (newa@tl)
in
keep_simplified_aux ~new_cl:true cl (alist,atable) bag []
- ;;
-
+ ;;
+
+ let are_alpha_eq cl1 cl2 =
+ let get_term (_,lit,_,_) =
+ match lit with
+ | Terms.Predicate _ -> assert false
+ | Terms.Equation (l,r,ty,_) ->
+ Terms.Node [Terms.Leaf B.eqP; ty; l ; r]
+ in
+ try ignore(Unif.alpha_eq (get_term cl1) (get_term cl2)) ; true
+ with FoUnif.UnificationFailure _ -> false
+;;
+
(* this is like simplify but raises Success *)
- let simplify_goal maxvar table bag clause =
- let bag, clause = demodulate bag clause table in
- if (is_identity_clause clause)
+ let simplify_goal ~no_demod maxvar table bag g_actives clause =
+ let bag, clause =
+ if no_demod then bag, clause else demodulate bag clause table
+ in
+ if List.exists (are_alpha_eq clause) g_actives then None else
+ if (is_identity_clause ~unify:true clause)
then raise (Success (bag, maxvar, clause))
+ else
+ let (id,lit,vl,_) = clause in
+ let l,r,ty =
+ match lit with
+ | Terms.Equation(l,r,ty,_) -> l,r,ty
+ | _ -> assert false
+ in
+ match deep_eq ~unify:true l r ty [] (fun x -> x) (fun x -> x)
+ table (Some(bag,maxvar,clause,Subst.id_subst)) with
+ | None -> Some (bag,clause)
+ | Some (bag,maxvar,cl,subst) ->
+ prerr_endline "Goal subsumed";
+ raise (Success (bag,maxvar,cl))
+(*
else match is_subsumed ~unify:true bag maxvar clause table with
- | None -> bag, clause
+ | None -> Some (bag, clause)
| Some ((bag,maxvar),c) ->
- debug "Goal subsumed";
+ prerr_endline "Goal subsumed";
raise (Success (bag,maxvar,c))
+*)
;;
(* =================== inference ===================== *)
in
debug "Another superposition";
let new_clauses = new_clauses @ additional_new_clauses in
+ debug (Printf.sprintf "Demodulating %d clauses"
+ (List.length new_clauses));
let bag, new_clauses =
- HExtlib.filter_map_acc (simplify atable maxvar) bag new_clauses
+ HExtlib.filter_map_monad (simplify atable maxvar) bag new_clauses
in
debug "Demodulated new clauses";
bag, maxvar, (alist, atable), new_clauses
superposition_with_table bag maxvar goal atable
in
debug "Superposed goal with active clauses";
- (* We demodulate the new goals with active clauses *)
+ (* We simplify the new goals with active clauses *)
let bag, new_goals =
List.fold_left
(fun (bag, acc) g ->
- let bag, g = demodulate bag g atable in
- bag, g :: acc)
+ match simplify_goal ~no_demod:false maxvar atable bag [] g with
+ | None -> assert false
+ | Some (bag,g) -> bag,g::acc)
(bag, []) new_goals
in
- debug "Demodulated goal with active clauses";
+ debug "Simplified new goals with active clauses";
bag, maxvar, List.rev new_goals
;;
projects / helm.git / blobdiff