From 249a5bb51142808774d736824473513c6ef68260 Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Wed, 8 Jul 2020 23:18:12 -0500
Subject: [PATCH] Adding an XML node constructor for the DAGUniverse.

---
 include/openmc/cell.h |  3 +++
 src/dagmc.cpp         | 60 ++++++++++++++++++++++++-------------------
 2 files changed, 37 insertions(+), 26 deletions(-)

diff --git a/include/openmc/cell.h b/include/openmc/cell.h
index 5b0b595608..52d6e9fdc6 100644
--- a/include/openmc/cell.h
+++ b/include/openmc/cell.h
@@ -80,10 +80,13 @@ public:
 class DAGUniverse : public Universe {
 
 public:
+  explicit DAGUniverse(pugi::xml_node node);
   explicit DAGUniverse(const std::string& filename);
 
+  void initialize(); //!< Sets up the DAGMC instance and OpenMC internals
 
   // Data Members
+  std::string filename_;
   std::shared_ptr<moab::DagMC> dagmc_instance_; //! DAGMC Instance for this universe
 };
 
diff --git a/src/dagmc.cpp b/src/dagmc.cpp
index 37de2d0c6e..395372a58d 100644
--- a/src/dagmc.cpp
+++ b/src/dagmc.cpp
@@ -155,7 +155,37 @@ void load_dagmc_geometry()
   model::universe_map[model::universes.back()->id_] = model::universes.size() - 1;
 }
 
-DAGUniverse::DAGUniverse(const std::string& filename) {
+DAGUniverse::DAGUniverse(pugi::xml_node node) {
+  if (check_for_node(node, "id")) {
+    id_ = std::stoi(get_node_value(node, "id"));
+  } else {
+    fatal_error("Must specify the id of the DAGMC universe");
+  }
+
+  if (check_for_node(node, "filename")) {
+    filename_ = get_node_value(node, "filename");
+  } else {
+    fatal_error("Must specify a file for the DAGMC universe");
+  }
+
+  initialize();
+}
+
+DAGUniverse::DAGUniverse(const std::string& filename) : filename_(filename) {
+  // determine the next universe id
+  int32_t next_univ_id = 0;
+  for (const auto& u : model::universes) {
+    if (u->id_ > next_univ_id) next_univ_id = u->id_;
+  }
+  next_univ_id++;
+
+  // set the universe id
+  id_ = next_univ_id;
+
+  initialize();
+}
+
+void DAGUniverse::initialize() {
 
   // determine the next cell id
   int32_t next_cell_id = 0;
@@ -171,23 +201,13 @@ DAGUniverse::DAGUniverse(const std::string& filename) {
   }
   next_surf_id++;
 
-  // determine the next universe id
-  int32_t next_univ_id = 0;
-  for (const auto& u : model::universes) {
-    if (u->id_ > next_univ_id) next_univ_id = u->id_;
-  }
-  next_univ_id++;
-
-  // set the universe id
-  id_ = next_univ_id;
-
   // create a new DAGMC instance
   dagmc_instance_ = std::make_shared<moab::DagMC>();
 
   // --- Materials ---
 
   // create uwuw instance
-  UWUW uwuw(filename.c_str());
+  UWUW uwuw(filename_.c_str());
 
   // check for uwuw material definitions
   bool using_uwuw = !uwuw.material_library.empty();
@@ -198,7 +218,7 @@ DAGUniverse::DAGUniverse(const std::string& filename) {
   }
 
   // load the DAGMC geometry
-  moab::ErrorCode rval = dagmc_instance_->load_file(filename.c_str());
+  moab::ErrorCode rval = dagmc_instance_->load_file(filename_.c_str());
   MB_CHK_ERR_CONT(rval);
 
   // initialize acceleration data structures
@@ -237,17 +257,6 @@ DAGUniverse::DAGUniverse(const std::string& filename) {
     model::cell_map[c->id_] = model::cells.size() - 1;
     cells_.push_back(model::cell_map[c->id_]);
 
-    // Populate the Universe vector and dict
-    // auto it = model::universe_map.find(dagmc_univ_id);
-    // if (it == model::universe_map.end()) {
-    //   model::universes.push_back(std::make_unique<Universe>());
-    //   model::universes.back()->id_ = dagmc_univ_id;
-    //   model::universes.back()->cells_.push_back(i);
-    //   model::universe_map[id_] = model::universes.size() - 1;
-    // } else {
-    //   model::universes[it->second]->cells_.push_back(i);
-    // }
-
     // MATERIALS
 
     // determine volume material assignment
@@ -554,8 +563,7 @@ void read_geometry_dagmc()
 {
   write_message("Reading DAGMC geometry...", 5);
   load_dagmc_geometry();
-
-  model::root_universe = 0;
+  model::root_universe = find_root_universe();
 }
 
 }