X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Fsuperposition.ml;h=ffca04b96c7ff7b2c84f2cdde3953ed97b787df2;hb=eca915d2656084f1e58149a476a2d305758b00f9;hp=d823c5a533bd8c5bab86d63b5ba98da5b9d34af4;hpb=c091ca7a030a85a529543de98e45c54284028b63;p=helm.git diff --git a/helm/software/components/ng_paramodulation/superposition.ml b/helm/software/components/ng_paramodulation/superposition.ml index d823c5a53..ffca04b96 100644 --- a/helm/software/components/ng_paramodulation/superposition.ml +++ b/helm/software/components/ng_paramodulation/superposition.ml @@ -23,7 +23,7 @@ module Superposition (B : Terms.Blob) = exception Success of B.t Terms.bag * int * B.t Terms.unit_clause let debug s = - () (* prerr_endline s *) + () (* prerr_endline s *) ;; let rec list_first f = function @@ -35,7 +35,7 @@ module Superposition (B : Terms.Blob) = let rec aux pos ctx = function | Terms.Leaf _ as t -> f t pos ctx | Terms.Var _ -> None - | Terms.Node l as t-> + | Terms.Node l as t-> match f t pos ctx with | Some _ as x -> x | None -> @@ -120,7 +120,7 @@ module Superposition (B : Terms.Blob) = 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: " ^ @@ -133,26 +133,48 @@ module Superposition (B : Terms.Blob) = (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)));*) - let t = - match literal with - | Terms.Predicate t -> t - | Terms.Equation (l,r,ty,_) -> Terms.Node [ Terms.Leaf B.eqP; ty; l; r ] - in - match first_position [] (fun x -> x) t (demod table vl) 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 literal with + | Terms.Predicate t -> assert false + | Terms.Equation (l,r,ty,_) -> + 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) -> + 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 + (demod table vl) + with + | None -> None + | Some (newt, subst, varlist, 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 *) @@ -310,15 +332,28 @@ module Superposition (B : Terms.Blob) = 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) then raise (Success (bag, maxvar, clause)) 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)) @@ -429,6 +464,8 @@ module Superposition (B : Terms.Blob) = 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 in @@ -438,17 +475,20 @@ module Superposition (B : Terms.Blob) = let infer_left bag maxvar goal (_alist, atable) = (* We superpose the goal with active clauses *) - let bag, maxvar, new_goals = + let bag, maxvar, new_goals = superposition_with_table bag maxvar goal atable in - (* We demodulate the goal with active clauses *) + debug "Superposed goal 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 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"; bag, maxvar, List.rev new_goals ;;