From f673a8dad277138a4eca3a874b2f44ffb4001751 Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Fri, 12 Mar 2021 10:32:14 -0600
Subject: [PATCH] A couple more changes for robustness.

---
 src/mesh.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/mesh.cpp b/src/mesh.cpp
index 30553c8c74..333a5dc331 100644
--- a/src/mesh.cpp
+++ b/src/mesh.cpp
@@ -60,7 +60,7 @@ std::vector<std::unique_ptr<Mesh>> meshes;
 #ifdef LIBMESH
 namespace settings {
 std::unique_ptr<libMesh::LibMeshInit> libmesh_init;
-const libMesh::Parallel::Communicator* libmesh_comm;
+const libMesh::Parallel::Communicator* libmesh_comm {nullptr};
 }
 #endif
 
@@ -2155,6 +2155,9 @@ void LibMesh::initialize()
     fatal_error("Attempting to use an unstructured mesh without a libMesh communicator.");
   }
 
+  // assuming that unstructured meshes used in OpenMC are 3D
+  n_dimension_ = 3;
+
   m_ = std::make_unique<libMesh::Mesh>(*settings::libmesh_comm, n_dimension_);
   m_->read(filename_);
   m_->prepare_for_use();