X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Fsuperposition.ml;h=61d6c0589f3ab9952e670ead382f71633ea00ef8;hb=1c9b8f3ba2c86446d44160ae494bc85624bc5eaf;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..61d6c0589 100644
--- a/helm/software/components/ng_paramodulation/superposition.ml
+++ b/helm/software/components/ng_paramodulation/superposition.ml
@@ -178,12 +178,13 @@ 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.Predicate _, _, _ -> assert false	  
+      | _ -> false
     ;;
 
     let build_new_clause bag maxvar filter rule t subst vl id id2 pos dir =
@@ -205,46 +206,68 @@ 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 
     ;;
 
+(*
+    let rec deeply_subsumed ~unify bag maxvar (id, lit, vl, _) table =
+      match lit with
+      | Terms.Predicate _ -> assert false
+      | Terms.Equation (l,r,ty,_) -> 
+	(match is_subsumed ~unify bag maxvar (id, lit, vl, _) table with
+	 | Some((bag,maxvar),c) -> Some((bag,maxvar),c)
+	 | None -> 
+	     match l,r with ->
+	       Var i, _ -> 
+    ;;
+*)	  
+
+
     (* 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 None
       else
         match is_subsumed ~unify:false bag maxvar clause table with
 	  | None -> Some (bag, clause)
@@ -350,7 +373,7 @@ 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)
+      if (is_identity_clause ~unify:true clause)
       then raise (Success (bag, maxvar, clause))
       else match is_subsumed ~unify:true bag maxvar clause table with
 	| None ->