From 51217b34759f33277c7485411a6d494941753923 Mon Sep 17 00:00:00 2001
From: Timo Heister <timo.heister@gmail.com>
Date: Fri, 23 Jan 2015 09:34:01 -0500
Subject: [PATCH] fix tests/mpi/step-39

And yes, making a copy of the matrix was indeed a mistake here.
---
 tests/mpi/step-39.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/mpi/step-39.cc b/tests/mpi/step-39.cc
index f9ee1d0ee1..9180b959cf 100644
--- a/tests/mpi/step-39.cc
+++ b/tests/mpi/step-39.cc
@@ -563,7 +563,7 @@ namespace Step39
     SolverControl coarse_solver_control (1000, 1e-10, false, false);
     SolverCG<TrilinosWrappers::MPI::Vector> coarse_solver(coarse_solver_control);
     PreconditionIdentity identity;
-    TrilinosWrappers::SparseMatrix coarse_matrix = mg_matrix[0];
+    TrilinosWrappers::SparseMatrix & coarse_matrix = mg_matrix[0];
     MGCoarseGridLACIteration<SolverCG<TrilinosWrappers::MPI::Vector>,TrilinosWrappers::MPI::Vector>
     coarse_grid_solver(coarse_solver, coarse_matrix, identity);
 
-- 
2.39.5