X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Fsuperposition.ml;h=6f1fb0f7f91a3e1395bf3dc71fa6a65cb39a3136;hb=dce1bca274f93a3bddcc0f6b04cbf126ccff42b0;hp=f69de41f553929765cc3e0cd393211939e38b2e2;hpb=b68e52f889215ce2c21c3d771f59b2d2057d53c1;p=helm.git diff --git a/helm/software/components/ng_paramodulation/superposition.ml b/helm/software/components/ng_paramodulation/superposition.ml index f69de41f5..6f1fb0f7f 100644 --- a/helm/software/components/ng_paramodulation/superposition.ml +++ b/helm/software/components/ng_paramodulation/superposition.ml @@ -20,10 +20,14 @@ module Superposition (B : Orderings.Blob) = module Utils = FoUtils.Utils(B) module Pp = Pp.Pp(B) - exception Success of B.t Terms.bag * int * B.t Terms.unit_clause - - let debug s = prerr_endline s;; - let debug _ = ();; + exception Success of + B.t Terms.bag + * int + * B.t Terms.unit_clause + * B.t Terms.substitution + + (* let debug s = prerr_endline (Lazy.force s);; *) + let debug _ = ();; let enable = true;; let rec list_first f = function @@ -81,7 +85,7 @@ module Superposition (B : Orderings.Blob) = let rec aux bag pos ctx id = function | Terms.Leaf _ as t -> f bag t pos ctx id | Terms.Var _ as t -> bag,t,id - | Terms.Node l as t-> + | Terms.Node (hd::l) as t-> let bag,t,id1 = f bag t pos ctx id in if id = id1 then let bag, l, _, id = @@ -92,13 +96,43 @@ module Superposition (B : Orderings.Blob) = let bag,newt,id = aux bag newpos newctx id t in if post = [] then bag, pre@[newt], [], id else bag, pre @ [newt], List.tl post, id) - (bag, [], List.tl l, id) l + (bag, [hd], List.tl l, id) l in bag, Terms.Node l, id - else bag,t,id1 + else bag,t,id1 + (* else aux bag pos ctx id1 t *) + | _ -> assert false in aux bag pos ctx id t ;; + + let visit bag pos ctx id t f = + let rec aux bag pos ctx id subst = function + | Terms.Leaf _ as t -> + let bag,subst,t,id = f bag t pos ctx id + in assert (subst=[]); bag,t,id + | Terms.Var i as t -> + let t= Subst.apply_subst subst t in + bag,t,id + | Terms.Node (hd::l) -> + let bag, l, _, id = + List.fold_left + (fun (bag,pre,post,id) t -> + let newctx = fun x -> ctx (Terms.Node (pre@[x]@post)) in + let newpos = (List.length pre)::pos in + let bag,newt,id = aux bag newpos newctx id subst t in + if post = [] then bag, pre@[newt], [], id + else bag, pre @ [newt], List.tl post, id) + (bag, [hd], List.map (Subst.apply_subst subst) (List.tl l), id) l + in + let bag,subst,t,id1 = f bag (Terms.Node l) pos ctx id + in + if id1 = id then (assert (subst=[]); bag,t,id) + else aux bag pos ctx id1 subst t + | _ -> assert false + in + aux bag pos ctx id [] t + ;; let build_clause bag filter rule t subst id id2 pos dir = let proof = Terms.Step(rule,id,id2,dir,pos,subst) in @@ -144,7 +178,7 @@ module Superposition (B : Orderings.Blob) = try let subst = prof_demod_u.HExtlib.profile - (Unif.unification (varlist@vl) varlist subterm) side + (Unif.unification (* (varlist@vl) *) varlist subterm) side in let side = prof_demod_s.HExtlib.profile @@ -154,7 +188,7 @@ module Superposition (B : Orderings.Blob) = prof_demod_s.HExtlib.profile (Subst.apply_subst subst) newside in - if o = Terms.Incomparable then + if o = Terms.Incomparable || o = Terms.Invertible then let o = prof_demod_o.HExtlib.profile (Order.compare_terms newside) side in @@ -176,38 +210,82 @@ module Superposition (B : Orderings.Blob) = prof_demod.HExtlib.profile (demod table varlist) x ;; - let demodulate_once_old ~jump_to_right bag (id, literal, vl, pr) table = - match literal with + let mydemod table varlist subterm = + let cands = + prof_demod_r.HExtlib.profile + (IDX.DT.retrieve_generalizations table) subterm + in + list_first + (fun (dir, ((id,lit,vl,_) as c)) -> + debug (lazy("candidate: " + ^ Pp.pp_unit_clause c)); + match lit with + | Terms.Predicate _ -> assert false + | Terms.Equation (l,r,_,o) -> + let side, newside = if dir=Terms.Left2Right then l,r else r,l in + try + let subst = + prof_demod_u.HExtlib.profile + (Unif.unification (* (varlist@vl) *) varlist subterm) side + in + let iside = + prof_demod_s.HExtlib.profile + (Subst.apply_subst subst) side + in + let inewside = + prof_demod_s.HExtlib.profile + (Subst.apply_subst subst) newside + in + if o = Terms.Incomparable || o = Terms.Invertible then + let o = + prof_demod_o.HExtlib.profile + (Order.compare_terms inewside) iside in + (* Riazanov, pp. 45 (ii) *) + if o = Terms.Lt then + Some (newside, subst, id, dir) + else + ((*prerr_endline ("Filtering: " ^ + Pp.pp_foterm side ^ " =(< || =)" ^ + Pp.pp_foterm newside ^ " coming from " ^ + Pp.pp_unit_clause uc );*)None) + else + Some (newside, subst, id, dir) + with FoUnif.UnificationFailure _ -> None) + (IDX.ClauseSet.elements cands) + ;; + + let ctx_demod table vl bag t pos ctx id = + match mydemod table vl t with + | None -> (bag,[],t,id) + | Some (newside, subst, id2, dir) -> + let inewside = Subst.apply_subst subst newside in + match build_clause bag (fun _ -> true) + Terms.Demodulation (ctx inewside) subst id id2 pos dir + with + | None -> assert false + | Some (bag,(id,_,_,_)) -> + (bag,subst,newside,id) + ;; + + let rec demodulate bag (id, literal, vl, pr) table = + debug (lazy "demodulate..."); + 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, id2, dir, pos) -> - begin - match build_clause bag (fun _ -> true) Terms.Demodulation - newt subst 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, id2, dir, pos) -> - match build_clause bag (fun _ -> true) - Terms.Demodulation newt subst id id2 pos dir - with - | None -> assert false - | Some x -> Some (x,true) + let bag,l,id1 = + visit bag [2] + (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; x; r ]) id l + (ctx_demod table vl) + in + let bag,_,id2 = + visit bag [3] + (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; l; x ]) id1 r + (ctx_demod table vl) + in + let cl,_,_ = Terms.get_from_bag id2 bag in + bag,cl ;; - + let parallel_demod table vl bag t pos ctx id = match demod table vl t with | None -> (bag,t,id) @@ -220,41 +298,6 @@ module Superposition (B : Orderings.Blob) = (bag,newside,id) ;; - let demodulate_once ~jump_to_right bag (id, literal, vl, pr) table = - match literal with - | Terms.Predicate t -> assert false - | Terms.Equation (l,r,ty,_) -> - let bag,l,id1 = if jump_to_right then (bag,l,id) else - parallel_positions bag [2] - (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; x; r ]) id l - (parallel_demod table vl) - in - let jump_to_right = id1 = id in - let bag,r,id2 = - parallel_positions bag [3] - (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; l; x ]) id1 r - (parallel_demod table vl) - in - if id = id2 then None - else - let cl,_,_ = Terms.get_from_bag id2 bag in - Some ((bag,cl),jump_to_right) - ;; - - 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),r) -> demodulate ~jump_to_right:r - bag clause table - ;; - - let rec demodulate_old ~jump_to_right bag clause table = - match demodulate_once_old ~jump_to_right bag clause table with - | None -> bag, clause - | Some ((bag, clause),r) -> demodulate_old ~jump_to_right:r - bag clause table - ;; - let are_alpha_eq cl1 cl2 = let get_term (_,lit,_,_) = match lit with @@ -266,35 +309,27 @@ module Superposition (B : Orderings.Blob) = with FoUnif.UnificationFailure _ -> false ;; - let demodulate bag clause table = -(* let (bag1,c1), (_,c2) =*) - demodulate ~jump_to_right:false bag clause table -(* demodulate_old ~jump_to_right:false bag clause table *) -(* in - if are_alpha_eq c1 c2 then bag1,c1 - else begin - prerr_endline (Pp.pp_unit_clause c1); - prerr_endline (Pp.pp_unit_clause c2); - prerr_endline "Bag :"; - prerr_endline (Pp.pp_bag bag1); - assert false - end*) - ;; let prof_demodulate = HExtlib.profile ~enable "demodulate";; let demodulate bag clause x = prof_demodulate.HExtlib.profile (demodulate bag clause) x ;; (* move away *) - let is_identity_clause ~unify = function + let is_identity_clause = function | _, Terms.Equation (_,_,_,Terms.Eq), _, _ -> true - | _, 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 is_identity_goal = function + | _, Terms.Equation (_,_,_,Terms.Eq), _, _ -> Some [] + | _, Terms.Equation (l,r,_,_), vl, proof -> + (try Some (Unif.unification (* vl *) [] l r) + with FoUnif.UnificationFailure _ -> None) + | _, Terms.Equation (_,_,_,_), _, _ -> None + | _, Terms.Predicate _, _, _ -> assert false + ;; + let build_new_clause bag maxvar filter rule t subst id id2 pos dir = let maxvar, _vl, subst = Utils.relocate maxvar (Terms.vars_of_term (Subst.apply_subst subst t)) subst in @@ -317,7 +352,6 @@ module Superposition (B : Orderings.Blob) = in bag, maxvar, res ;; - let rewrite_eq ~unify l r ty vl table = let retrieve = if unify then IDX.DT.retrieve_unifiables @@ -343,7 +377,7 @@ module Superposition (B : Orderings.Blob) = | [] -> None | (id2,dir,c,vl1)::tl -> try - let subst = Unif.unification (vl@vl1) locked_vars c t in + let subst = Unif.unification (* (vl@vl1) *) locked_vars c t in Some (id2, dir, subst) with FoUnif.UnificationFailure _ -> aux tl in @@ -374,7 +408,7 @@ module Superposition (B : Orderings.Blob) = let l = Subst.apply_subst subst l in let r = Subst.apply_subst subst r in try - let subst1 = Unif.unification vl [] l r in + let subst1 = Unif.unification (* vl *) [] l r in let lit = match lit with Terms.Predicate _ -> assert false | Terms.Equation (l,r,ty,o) -> @@ -441,7 +475,7 @@ module Superposition (B : Orderings.Blob) = 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 + if res then debug (lazy "Orphan murdered"); res ;; let prof_orphan_murder = HExtlib.profile ~enable "orphan_murder";; let orphan_murder bag actives x = @@ -449,11 +483,12 @@ module Superposition (B : Orderings.Blob) = ;; (* demodulate and check for subsumption *) - let simplify table maxvar bag clause = - if is_identity_clause ~unify:false clause then bag,None + let simplify table maxvar bag clause = + debug (lazy "simplify..."); + if is_identity_clause 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 + if is_identity_clause clause then bag,None else match is_subsumed ~unify:false bag maxvar clause table with | None -> bag, Some clause @@ -565,7 +600,7 @@ module Superposition (B : Orderings.Blob) = | bag,(None, Some _) -> bag,None | bag,(Some cl1, Some (clause, (alist,atable), newa)) -> let alist,atable = - (clause::alist, IDX.index_unit_clause atable clause) + (clause::alist, IDX.index_unit_clause atable clause) in keep_simplified_aux ~new_cl:(cl!=cl1) cl1 (alist,atable) bag (newa@tl) @@ -582,12 +617,15 @@ module Superposition (B : Orderings.Blob) = 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 + if List.exists (are_alpha_eq clause) g_actives then None + else match (is_identity_goal clause) with + | Some subst -> raise (Success (bag,maxvar,clause,subst)) + | None -> let (id,lit,vl,_) = clause in - if vl = [] then Some (bag,clause) + (* this optimization makes sense only if we demodulated, since in + that case the clause should have been turned into an identity *) + if (vl = [] && not(no_demod)) + then Some (bag,clause) else let l,r,ty = match lit with @@ -598,15 +636,15 @@ module Superposition (B : Orderings.Blob) = 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)) + debug (lazy "Goal subsumed"); + raise (Success (bag,maxvar,cl,subst)) (* - else match is_subsumed ~unify:true bag maxvar clause table with + match is_subsumed ~unify:true bag maxvar clause table with | None -> Some (bag, clause) | Some ((bag,maxvar),c) -> prerr_endline "Goal subsumed"; raise (Success (bag,maxvar,c)) -*) +*) ;; let prof_simplify_goal = HExtlib.profile ~enable "simplify_goal";; @@ -627,9 +665,9 @@ module Superposition (B : Orderings.Blob) = let side, newside = if dir=Terms.Left2Right then l,r else r,l in try let subst = - Unif.unification (varlist@vl) [] subterm side + Unif.unification (* (varlist@vl)*) [] subterm side in - if o = Terms.Incomparable then + if o = Terms.Incomparable || o = Terms.Invertible then let side = Subst.apply_subst subst side in let newside = Subst.apply_subst subst newside in let o = Order.compare_terms side newside in @@ -656,6 +694,7 @@ module Superposition (B : Orderings.Blob) = (all_positions [3] (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; l; x ]) r (superposition table vl)) + | Terms.Equation (l,r,ty,Terms.Invertible) | Terms.Equation (l,r,ty,Terms.Gt) -> fold_build_new_clause bag maxvar id Terms.Superposition (fun _ -> true) @@ -680,8 +719,8 @@ module Superposition (B : Orderings.Blob) = fold_build_new_clause bag maxvar id Terms.Superposition (filtering Terms.Lt) (all_positions [2] - (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; l; x ]) - r (superposition table vl)) + (fun x -> Terms.Node [ Terms.Leaf B.eqP; ty; x; r ]) + l (superposition table vl)) in bag, maxvar, r_terms @ l_terms | _ -> assert false @@ -700,7 +739,7 @@ module Superposition (B : Orderings.Blob) = in bag, (alist, List.fold_left IDX.index_unit_clause IDX.DT.empty alist) in*) - debug "Simplified active clauses with fact"; + debug (lazy "Simplified active clauses with fact"); (* We superpose active clauses with current *) let bag, maxvar, new_clauses = List.fold_left @@ -711,13 +750,13 @@ module Superposition (B : Orderings.Blob) = bag, maxvar, newc @ acc) (bag, maxvar, []) alist in - debug "First superpositions"; + debug (lazy "First superpositions"); (* We add current to active clauses so that it can be * * superposed with itself *) let alist, atable = current :: alist, IDX.index_unit_clause atable current in - debug "Indexed"; + debug (lazy "Indexed"); let fresh_current, maxvar = Utils.fresh_unit_clause maxvar current in (* We need to put fresh_current into the bag so that all * * variables clauses refer to are known. *) @@ -726,14 +765,14 @@ module Superposition (B : Orderings.Blob) = let bag, maxvar, additional_new_clauses = superposition_with_table bag maxvar fresh_current atable in - debug "Another superposition"; + debug (lazy "Another superposition"); let new_clauses = new_clauses @ additional_new_clauses in - debug (Printf.sprintf "Demodulating %d clauses" - (List.length new_clauses)); + (* debug (lazy (Printf.sprintf "Demodulating %d clauses" + (List.length new_clauses))); *) let bag, new_clauses = HExtlib.filter_map_monad (simplify atable maxvar) bag new_clauses in - debug "Demodulated new clauses"; + debug (lazy "Demodulated new clauses"); bag, maxvar, (alist, atable), new_clauses ;; @@ -749,7 +788,7 @@ module Superposition (B : Orderings.Blob) = let bag, maxvar, new_goals = superposition_with_table bag maxvar goal atable in - debug "Superposed goal with active clauses"; + debug(lazy "Superposed goal with active clauses"); (* We simplify the new goals with active clauses *) let bag, new_goals = List.fold_left @@ -759,7 +798,7 @@ module Superposition (B : Orderings.Blob) = | Some (bag,g) -> bag,g::acc) (bag, []) new_goals in - debug "Simplified new goals with active clauses"; + debug (lazy "Simplified new goals with active clauses"); bag, maxvar, List.rev new_goals ;;