One-side indexing for commutativity

[helm.git] / helm / software / components / ng_paramodulation / index.ml

diff --git a/helm/software/components/ng_paramodulation/index.ml b/helm/software/components/ng_paramodulation/index.ml
index 889e1e7ef14955960fb1b88bbb7d8f40581ecf1c..5c085c5188db5a4473337995e167d17b290f5bfe 100644 (file)
--- a/helm/software/components/ng_paramodulation/index.ml
+++ b/helm/software/components/ng_paramodulation/index.ml
@@ -13,6 +13,8 @@
 
 module Index(B : Orderings.Blob) = struct
   module U = FoUtils.Utils(B)
+  module Unif = FoUnif.Founif(B)
+  module Pp = Pp.Pp(B)
 
   module ClauseOT =
     struct 
@@ -79,12 +81,23 @@ module Index(B : Orderings.Blob) = struct
       type dataset = ClauseSet.t
     = Make(FotermIndexable)(ClauseSet)
 
-  let index_unit_clause t = function
+  let are_invertible maxvar varlist l r =
+    let _,_,subst = U.relocate maxvar varlist FoSubst.id_subst in
+    let l = FoSubst.apply_subst subst l in
+      try (ignore(Unif.alpha_eq l r);true) with
+         FoUnif.UnificationFailure _ -> false
+  
+  let index_unit_clause maxvar t = function
     | (_,Terms.Equation (l,_,_,Terms.Gt),_,_) as c -> 
           DT.index t l (Terms.Left2Right, c)
     | (_,Terms.Equation (_,r,_,Terms.Lt),_,_) as c -> 
           DT.index t r (Terms.Right2Left, c)
-    | (_,Terms.Equation (l,r,_,Terms.Incomparable),_,_) as c ->  
+    | (_,Terms.Equation (l,r,_,Terms.Incomparable),vl,_) as c ->
+       if are_invertible maxvar vl l r then
+         (prerr_endline ("Invertible " ^ (Pp.pp_foterm l) ^ "=" ^
+            (Pp.pp_foterm r));
+           DT.index t l (Terms.Left2Right, c))
+          else
           DT.index  
            (DT.index t l (Terms.Left2Right, c))
            r (Terms.Right2Left, c)