From f72be45dd5ef2207a23ace57af3e37095f395664 Mon Sep 17 00:00:00 2001
From: Matthias Maier <tamiko@43-1.org>
Date: Thu, 3 May 2018 13:40:15 -0500
Subject: [PATCH] Bugfix: Use the general vector interface

We should really try hard to avoid using implementation specific low
level access via operator[].
---
 include/deal.II/lac/linear_operator.h | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/deal.II/lac/linear_operator.h b/include/deal.II/lac/linear_operator.h
index 874d795d5a..97a5a20946 100644
--- a/include/deal.II/lac/linear_operator.h
+++ b/include/deal.II/lac/linear_operator.h
@@ -866,15 +866,17 @@ mean_value_filter(const std::function<void(Range &, bool)> &reinit_vector)
   return_op.vmult = [](Range &v, const Range &u)
   {
     const auto mean = u.mean_value();
-    for (types::global_dof_index i = 0; i<v.size(); ++i)
-      v(i) = u(i) - mean;
+
+    v = u;
+    v.add(-mean);
   };
 
   return_op.vmult_add = [](Range &v, const Range &u)
   {
     const auto mean = u.mean_value();
-    for (types::global_dof_index i = 0; i<v.size(); ++i)
-      v(i) += u(i) - mean;
+
+    v += u;
+    v.add(-mean);
   };
 
   return_op.Tvmult = return_op.vmult_add;
-- 
2.39.5