diff --git a/Geo/STensor3.h b/Geo/STensor3.h
index 5af500c52b95c4b7e918981322d861d7153153b3..3562f71e904800419d5a308000f2257e994d4444 100644
--- a/Geo/STensor3.h
+++ b/Geo/STensor3.h
@@ -227,6 +227,14 @@ class STensor3 {
   {
     return _val[getIndex(i, j)];
   }
+  inline double operator[](int i) const
+  {
+    return _val[i];
+  }
+  inline double &operator[](int i)
+  {
+    return _val[i];
+  }
   STensor3 invert () const
   {
     fullMatrix<double> m(3, 3);