;;
(* 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,[],subst) -> assert false
+ | Some(bag,maxvar,(id,_,vl,_)::clauses,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
+ Some(bag,maxvar,clauses,Subst.concat subst1 subst)
+ with FoUnif.UnificationFailure _ ->
+ match rewrite_eq ~unify l r ty vl table with
+ | Some (id2, dir, subst1) ->
+ let id_t =
+ 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 (2::pos) dir
+ with
+ | Some ((bag, maxvar), c) ->
+ Some(bag,maxvar,c::clauses,Subst.concat subst1 subst)
+ | 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
+ | Terms.Var _, _
+ | _, Terms.Var _ -> assert false
+ | _,_ -> None
;;
(* 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
match is_subsumed ~unify:false bag maxvar clause table with
- | None -> Some (bag, clause)
- | Some _ -> None
+ | None -> bag, Some clause
+ | Some _ -> bag, None
;;
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 -> 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 ->
match simplify ctable maxvar bag c with
- |None -> acc (* an active clause as been discarded *)
- |Some (bag, c1) ->
+ |bag,None -> acc (* an active clause as been discarded *)
+ |bag,Some c1 ->
bag, c :: alist, IDX.index_unit_clause atable c)
(bag,[],IDX.DT.empty) alist
in
* - 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) ->
+ | bag,None -> (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
List.fold_left
(fun (bag, newa, alist, atable as acc) c ->
match simplify ctable maxvar bag c with
- |None -> acc (* an active clause as been discarded *)
- |Some (bag, c1) ->
+ |bag,None -> acc (* an active clause as been discarded *)
+ |bag,Some c1 ->
if (c1 == c) then
bag, newa, c :: alist,
IDX.index_unit_clause atable c
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) ->
+ | bag,Some cl1 ->
(Some cl1, Some (clause, (alist,atable), newa, bag))
;;
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 simplify_goal maxvar table bag g_actives clause =
let bag, clause = demodulate bag clause table in
- if (is_identity_clause clause)
+ 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 ->
+ if List.exists (are_alpha_eq clause) g_actives then None
+ else Some (bag, clause)
+ | Some (bag,maxvar,cl,subst) ->
+ debug "Goal subsumed";
+ raise (Success (bag,maxvar,List.hd cl))
+*)
else match is_subsumed ~unify:true bag maxvar clause table with
- | None -> bag, clause
+ | None ->
+ if List.exists (are_alpha_eq clause) g_actives then None
+ else Some (bag, clause)
| Some ((bag,maxvar),c) ->
debug "Goal subsumed";
- raise (Success (bag,maxvar,c))
+ raise (Success (bag,maxvar,c))
;;
(* =================== inference ===================== *)
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
let bag, new_goals =
List.fold_left
(fun (bag, acc) g ->
- let bag, g = simplify_goal maxvar atable bag g in
- bag,g::acc)
+ match simplify_goal maxvar atable bag [] g with
+ | None -> assert false
+ | Some (bag,g) -> bag,g::acc)
(bag, []) new_goals
in
debug "Simplified new goals with active clauses";
projects / helm.git / blobdiff