From 0076cdc3cf96ce5d4e9212110406f8457d1f5c78 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Tue, 3 Apr 2018 10:31:00 -0600
Subject: [PATCH] Pass const scalar arguments by value, rather than reference.

---
 include/deal.II/grid/grid_tools.h | 6 +++---
 source/grid/grid_tools.cc         | 6 +++---
 source/grid/grid_tools.inst.in    | 7 +++++--
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/deal.II/grid/grid_tools.h b/include/deal.II/grid/grid_tools.h
index da0f37e578..42cd7989e4 100644
--- a/include/deal.II/grid/grid_tools.h
+++ b/include/deal.II/grid/grid_tools.h
@@ -1372,9 +1372,9 @@ namespace GridTools
   compute_mesh_predicate_bounding_box
   ( const MeshType                                                              &mesh,
     const std::function<bool (const typename MeshType::active_cell_iterator &)> &predicate,
-    const unsigned int                                                          &refinement_level = 0,
-    const bool                                                                  &allow_merge = false,
-    const unsigned int                                                          &max_boxes = numbers::invalid_unsigned_int);
+    const unsigned int                                                           refinement_level = 0,
+    const bool                                                                   allow_merge = false,
+    const unsigned int                                                           max_boxes = numbers::invalid_unsigned_int);
 
   /**
    * Given an array of points, use the global bounding box description obtained using
diff --git a/source/grid/grid_tools.cc b/source/grid/grid_tools.cc
index 5d126f1c0d..05d1ed41f6 100644
--- a/source/grid/grid_tools.cc
+++ b/source/grid/grid_tools.cc
@@ -1806,9 +1806,9 @@ next_cell:
   compute_mesh_predicate_bounding_box
   (const MeshType                                                              &mesh,
    const std::function<bool (const typename MeshType::active_cell_iterator &)> &predicate,
-   const unsigned int                                                          &refinement_level,
-   const bool                                                                  &allow_merge,
-   const unsigned int                                                          &max_boxes)
+   const unsigned int                                                           refinement_level,
+   const bool                                                                   allow_merge,
+   const unsigned int                                                           max_boxes)
   {
     // Algorithm brief description: begin with creating bounding boxes of all cells at
     // refinement_level (and coarser levels if there are active cells) which have the predicate
diff --git a/source/grid/grid_tools.inst.in b/source/grid/grid_tools.inst.in
index f8e55bc93b..53248ff85b 100644
--- a/source/grid/grid_tools.inst.in
+++ b/source/grid/grid_tools.inst.in
@@ -31,8 +31,11 @@ for (X : TRIANGULATIONS; deal_II_dimension : DIMENSIONS ; deal_II_space_dimensio
     template
     std::vector < BoundingBox< deal_II_space_dimension > >
     compute_mesh_predicate_bounding_box< X >
-    (const X &, const std::function<bool (const dealii::internal::ActiveCellIterator<deal_II_dimension, deal_II_space_dimension, X>::type&)> &,
-     const unsigned int &, const bool&, const unsigned int &);
+    (const X &,
+     const std::function<bool (const dealii::internal::ActiveCellIterator<deal_II_dimension, deal_II_space_dimension, X>::type&)> &,
+     const unsigned int,
+     const bool,
+     const unsigned int);
     \}
 
 #endif
-- 
2.39.5