From 781bc8adf57faf2ae94c8a5c415dba01e0e3c2c7 Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Tue, 17 Dec 2019 20:44:56 -0600
Subject: [PATCH] Adding equation system to mesh.

---
 include/openmc/mesh.h | 5 ++++-
 src/mesh.cpp          | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/openmc/mesh.h b/include/openmc/mesh.h
index 7470d6052..417097df7 100644
--- a/include/openmc/mesh.h
+++ b/include/openmc/mesh.h
@@ -24,9 +24,10 @@
 
 #ifdef LIBMESH
 #include "libmesh/libmesh.h"
+#include "libmesh/elem.h"
+#include "libmesh/equation_systems.h"
 #include "libmesh/mesh.h"
 #include "libmesh/point.h"
-#include "libmesh/elem.h"
 #endif
 
 namespace openmc {
@@ -509,6 +510,8 @@ public:
 private:
   std::unique_ptr<libMesh::Mesh> m_;
   std::unique_ptr<libMesh::PointLocatorBase> point_locator_;
+  std::unique_ptr<libMesh::EquationSystems> equation_systems_;
+  std::string eq_system_name_;
   libMesh::Elem* first_element_;
   std::set<libMesh::Elem*> boundary_elements_;
 };
diff --git a/src/mesh.cpp b/src/mesh.cpp
index edf0529e7..454cc9188 100644
--- a/src/mesh.cpp
+++ b/src/mesh.cpp
@@ -2054,6 +2054,13 @@ LibMesh::LibMesh(pugi::xml_node node) : UnstructuredMeshBase(node) {
 
   m_ = std::unique_ptr<libMesh::Mesh>(new libMesh::Mesh(settings::LMI->comm(), 3));
   m_->read(filename_);
+  m_->prepare_for_use();
+
+  eq_system_name_ = "mesh_" + std::to_string(id_) + "_system";
+
+  equation_systems_ =
+    std::unique_ptr<libMesh::EquationSystems>(new libMesh::EquationSystems(*m_));
+  auto& eq_sys = equation_systems_->add_system(eq_system_name_);
 
   point_locator_ = m_->sub_point_locator();
   point_locator_->enable_out_of_mesh_mode();