Fix grid alignment of refinement area

1 files changed, 2 insertions, 2 deletions

diff --git a/src/refinement/coupler2D.hh b/src/refinement/coupler2D.hh
index 5614d16..d599728 100644
--- a/src/refinement/coupler2D.hh
+++ b/src/refinement/coupler2D.hh
@@ -160,7 +160,7 @@ void FineCoupler2D<T,DESCRIPTOR>::interpolate()
 template <typename T, template<typename> class DESCRIPTOR>
 void FineCoupler2D<T,DESCRIPTOR>::couple()
 {
-  auto& coarseLattice = this->_coarse.getSuperLattice();
+  const auto& coarseLattice = this->_coarse.getSuperLattice();
   auto& fineLattice   = this->_fine.getSuperLattice();
 
   for (int y=0; y < this->_coarseSize; ++y) {
@@ -333,7 +333,7 @@ CoarseCoupler2D<T,DESCRIPTOR>::CoarseCoupler2D(
 template <typename T, template<typename> class DESCRIPTOR>
 void CoarseCoupler2D<T,DESCRIPTOR>::couple()
 {
-  auto& fineLattice = this->_fine.getSuperLattice();
+  const auto& fineLattice = this->_fine.getSuperLattice();
   auto& coarseLattice = this->_coarse.getSuperLattice();
 
   for (int y=0; y < this->_coarseSize; ++y) {