From d836a4dbe5033ecef4d32e2a26d59753c24d4340 Mon Sep 17 00:00:00 2001
From: Jean-Paul Pelteret <jppelteret@gmail.com>
Date: Fri, 8 Jan 2016 23:36:09 +0100
Subject: [PATCH] Tensor::operator[] should always return by reference.

One of the access operators returned by value, instead of by reference.
---
 doc/news/changes.h            | 6 ++++++
 include/deal.II/base/tensor.h | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/doc/news/changes.h b/doc/news/changes.h
index 0e879fb5cf..372805040d 100644
--- a/doc/news/changes.h
+++ b/doc/news/changes.h
@@ -198,6 +198,12 @@ inconvenience this causes.
 <a name="general"></a>
 <h3>General</h3>
 <ol>
+  <li> Fixed: Tensor::operator[] that takes TableIndices as a parameter no
+  longer returns by value, but rather by reference.
+  <br>
+  (Jean-Paul Pelteret, 2016/01/08)
+  </li>
+
   <li> New: constrained_linear_operator() and constrained_right_hand_side()
   provide a generic mechanism of applying constraints to a LinearOperator.
   A detailed explanation with example code is given in the @ref constraints
diff --git a/include/deal.II/base/tensor.h b/include/deal.II/base/tensor.h
index 125f964860..7aa7c52fc5 100644
--- a/include/deal.II/base/tensor.h
+++ b/include/deal.II/base/tensor.h
@@ -415,7 +415,7 @@ public:
   /**
    * Read access using TableIndices <tt>indices</tt>
    */
-  Number operator [] (const TableIndices<rank_> &indices) const;
+  const Number &operator [] (const TableIndices<rank_> &indices) const;
 
   /**
    * Read and write access using TableIndices <tt>indices</tt>
@@ -887,7 +887,7 @@ Tensor<rank_,dim,Number>::operator[] (const unsigned int i) const
 
 template <int rank_, int dim, typename Number>
 inline
-Number
+const Number &
 Tensor<rank_,dim,Number>::operator[] (const TableIndices<rank_> &indices) const
 {
   Assert(dim != 0, ExcMessage("Cannot access an object of type Tensor<rank_,0,Number>"));
-- 
2.39.5