From 775cc1ae19a80242aceed019e7af624a803ab3ad Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Tue, 2 Jun 2020 09:10:13 -0500
Subject: [PATCH] Incorporating @paulromano's comments

---
 include/openmc/cell.h    |  5 ++---
 include/openmc/lattice.h |  6 +++---
 src/cell.cpp             | 15 ++++++++-------
 src/lattice.cpp          |  8 ++++----
 4 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/include/openmc/cell.h b/include/openmc/cell.h
index ba905207ee..5efbdd99ef 100644
--- a/include/openmc/cell.h
+++ b/include/openmc/cell.h
@@ -5,7 +5,6 @@
 #include <functional> // for hash
 #include <limits>
 #include <memory> // for unique_ptr
-#include <set>
 #include <string>
 #include <unordered_map>
 #include <vector>
@@ -153,12 +152,12 @@ public:
   //! Get all cell instances contained by this cell
   //! \return Map with cell indexes as keys and instances as values
   std::unordered_map<int32_t, std::vector<int32_t>>
-  get_contained_cells();
+  get_contained_cells() const;
 
 protected:
   void
   get_contained_cells_inner(std::unordered_map<int32_t, std::vector<int32_t>>& contained_cells,
-                            std::vector<ParentCell>& parent_cells);
+                            std::vector<ParentCell>& parent_cells) const;
 
 public:
   //----------------------------------------------------------------------------
diff --git a/include/openmc/lattice.h b/include/openmc/lattice.h
index 4fc28b76b4..bf18d92e4b 100644
--- a/include/openmc/lattice.h
+++ b/include/openmc/lattice.h
@@ -134,7 +134,7 @@ public:
   //! \param indx The index for a lattice tile.
   //! \return Distribcell offset i.e. the largest instance number for the target
   //!  cell found in the geometry tree for this lattice index.
-  virtual int32_t& offset(int map, int indx) = 0;
+  virtual int32_t offset(int map, int indx) const = 0;
 
   //! \brief Convert an array index to a useful human-readable string.
   //! \param indx The index for a lattice tile.
@@ -227,7 +227,7 @@ public:
 
   int32_t& offset(int map, const int i_xyz[3]);
 
-  int32_t& offset(int map, int indx);
+  int32_t offset(int map, int indx) const;
 
   std::string index_to_string(int indx) const;
 
@@ -271,7 +271,7 @@ public:
 
   int32_t& offset(int map, const int i_xyz[3]);
 
-  int32_t& offset(int map, int indx);
+  int32_t offset(int map, int indx) const;
 
   std::string index_to_string(int indx) const;
 
diff --git a/src/cell.cpp b/src/cell.cpp
index 431d40b322..2761baa44f 100644
--- a/src/cell.cpp
+++ b/src/cell.cpp
@@ -5,6 +5,7 @@
 #include <cctype>
 #include <cmath>
 #include <iterator>
+#include <set>
 #include <sstream>
 #include <string>
 
@@ -275,8 +276,8 @@ Cell::set_temperature(double T, int32_t instance, bool set_contained)
       auto& cell = model::cells[entry.first];
       Expects(cell->type_ == Fill::MATERIAL);
       auto& instances =  entry.second;
-      for (auto instance = instances.begin(); instance != instances.end(); ++instance) {
-        cell->set_temperature(T, *instance);
+      for (auto instance : instances) {
+        cell->set_temperature(T, instance);
       }
     }
   }
@@ -1176,7 +1177,7 @@ openmc_cell_set_name(int32_t index, const char* name) {
 
 
 std::unordered_map<int32_t, std::vector<int32_t>>
-Cell::get_contained_cells() {
+Cell::get_contained_cells() const {
   std::unordered_map<int32_t, std::vector<int32_t>> contained_cells;
   std::vector<ParentCell> parent_cells;
 
@@ -1191,20 +1192,20 @@ Cell::get_contained_cells() {
 //! Get all cells within this cell
 void
 Cell::get_contained_cells_inner(std::unordered_map<int32_t, std::vector<int32_t>>& contained_cells,
-                                std::vector<ParentCell>& parent_cells)
+                                std::vector<ParentCell>& parent_cells) const
 {
 
   // filled by material, determine instance based on parent cells
   if (this->type_ == Fill::MATERIAL) {
     int instance = 0;
     if (this->distribcell_index_ >= 0) {
-      for (int i = 0; i < parent_cells.size(); i++) {
-        auto& cell = model::cells[parent_cells[i].cell_index];
+      for (auto& parent_cell : parent_cells) {
+        auto& cell = openmc::model::cells[parent_cell.cell_index];
         if (cell->type_ == Fill::UNIVERSE) {
           instance += cell->offset_[this->distribcell_index_];
         } else if (cell->type_ == Fill::LATTICE) {
           auto& lattice = model::lattices[cell->fill_];
-          instance += lattice->offset(this->distribcell_index_, parent_cells[i].lattice_index);
+          instance += lattice->offset(this->distribcell_index_, parent_cell.lattice_index);
         }
       }
     }
diff --git a/src/lattice.cpp b/src/lattice.cpp
index a3287982a3..f0c3dc979f 100644
--- a/src/lattice.cpp
+++ b/src/lattice.cpp
@@ -342,8 +342,8 @@ RectLattice::offset(int map, const int i_xyz[3])
 
 //==============================================================================
 
-int32_t&
-RectLattice::offset(int map, int indx)
+int32_t
+RectLattice::offset(int map, int indx) const
 {
   return offsets_[nx*ny*nz*map + indx];
 }
@@ -981,8 +981,8 @@ HexLattice::offset(int map, const int i_xyz[3])
   return offsets_[nx*ny*nz*map + nx*ny*i_xyz[2] + nx*i_xyz[1] + i_xyz[0]];
 }
 
-int32_t&
-HexLattice::offset(int map, int indx)
+int32_t
+HexLattice::offset(int map, int indx) const
 {
   int nx {2*n_rings_ - 1};
   int ny {2*n_rings_ - 1};