X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Fsuperposition.ml;h=96b16bb07b6a66dd674495d750e76075185faae2;hb=a872dba2b03e27967d5b9b51e950e85967340e52;hp=891c8dcacafaec6553e6884983448838fab7da1e;hpb=6f35dd77922431b667f7eb4669ab3fbb6092c343;p=helm.git diff --git a/helm/software/components/ng_paramodulation/superposition.ml b/helm/software/components/ng_paramodulation/superposition.ml index 891c8dcac..96b16bb07 100644 --- a/helm/software/components/ng_paramodulation/superposition.ml +++ b/helm/software/components/ng_paramodulation/superposition.ml @@ -15,16 +15,15 @@ module Superposition (B : Terms.Blob) = struct module IDX = Index.Index(B) module Unif = FoUnif.Founif(B) - module Subst = FoSubst (*.Subst(B)*) + module Subst = FoSubst module Order = Orderings.Orderings(B) 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 s = prerr_endline s;; + let debug _ = ();; let rec list_first f = function | [] -> None @@ -93,7 +92,7 @@ module Superposition (B : Terms.Blob) = | t -> Terms.Predicate t in let bag, uc = - Utils.add_to_bag bag (0, literal, vars_of_term t, proof) + Terms.add_to_bag (0, literal, vars_of_term t, proof) bag in Some (bag, uc) else @@ -134,7 +133,6 @@ module Superposition (B : Terms.Blob) = ;; 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,_) -> @@ -178,11 +176,12 @@ module Superposition (B : Terms.Blob) = ;; (* move away *) - let is_identity_clause = function + let is_identity_clause ~unify = function | _, Terms.Equation (_,_,_,Terms.Eq), _, _ -> true - | _, Terms.Equation (l,r,_,_), vl, proof -> + | _, 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 ;; @@ -194,7 +193,6 @@ module Superposition (B : Terms.Blob) = | None -> None ;; - let fold_build_new_clause bag maxvar id rule filter res = let (bag, maxvar), res = HExtlib.filter_map_acc @@ -205,67 +203,163 @@ module Superposition (B : Terms.Blob) = 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.get_from_bag 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 -> + Terms.replace_in_bag (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 = @@ -276,18 +370,20 @@ module Superposition (B : Terms.Blob) = (* 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 @@ -296,37 +392,37 @@ module Superposition (B : Terms.Blob) = (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 @@ -348,17 +444,35 @@ module Superposition (B : Terms.Blob) = ;; (* this is like simplify but raises Success *) - let simplify_goal maxvar table bag g_actives 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 + if vl = [] then Some (bag,clause) + else + 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 -> - if List.exists (are_alpha_eq clause) g_actives then None - else Some (bag, clause) + | None -> Some (bag, clause) | Some ((bag,maxvar),c) -> - debug "Goal subsumed"; + prerr_endline "Goal subsumed"; raise (Success (bag,maxvar,c)) +*) ;; (* =================== inference ===================== *) @@ -459,7 +573,7 @@ module Superposition (B : Terms.Blob) = 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. *) - let bag, fresh_current = Utils.add_to_bag bag fresh_current in + let bag, fresh_current = Terms.add_to_bag fresh_current bag in (* We superpose current with active clauses *) let bag, maxvar, additional_new_clauses = superposition_with_table bag maxvar fresh_current atable @@ -469,7 +583,7 @@ module Superposition (B : Terms.Blob) = 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 @@ -477,6 +591,8 @@ module Superposition (B : Terms.Blob) = let infer_left bag maxvar goal (_alist, atable) = (* We superpose the goal with active clauses *) + if (match goal with (_,_,[],_) -> true | _ -> false) then bag, maxvar, [] + else let bag, maxvar, new_goals = superposition_with_table bag maxvar goal atable in @@ -485,7 +601,7 @@ module Superposition (B : Terms.Blob) = let bag, new_goals = List.fold_left (fun (bag, acc) g -> - match simplify_goal maxvar atable bag [] g with + match simplify_goal ~no_demod:false maxvar atable bag [] g with | None -> assert false | Some (bag,g) -> bag,g::acc) (bag, []) new_goals