2 files changed, 9 insertions, 0 deletions
diff --git a/lib/util.ml b/lib/util.ml
index a9d9655eda..cd7f09de33 100644
--- a/lib/util.ml
+++ b/lib/util.ml
@@ -642,6 +642,13 @@ else
   let v' = Array.map (fun x -> let (y,e) = f x !e' in e' := e; y) v in
   (v',!e')
 
+let array_fold_map2' f v1 v2 e =
+  let e' = ref e in
+  let v' = 
+    array_map2 (fun x1 x2 -> let (y,e) = f x1 x2 !e' in e' := e; y) v1 v2 
+  in
+  (v',!e')
+
 (* Matrices *)
 
 let matrix_transpose mat =
diff --git a/lib/util.mli b/lib/util.mli
index e93094f898..52cd24127c 100644
--- a/lib/util.mli
+++ b/lib/util.mli
@@ -173,6 +173,8 @@ val array_map_left : ('a -> 'b) -> 'a array -> 'b array
 val array_map_left_pair : ('a -> 'b) -> 'a array -> ('c -> 'd) -> 'c array ->
   'b array * 'd array
 val array_fold_map' : ('a -> 'c -> 'b * 'c) -> 'a array -> 'c -> 'b array * 'c
+val array_fold_map2' :
+  ('a -> 'b -> 'c -> 'd * 'c) -> 'a array -> 'b array -> 'c -> 'd array * 'c
 
 (*s Matrices *)