Add constructor for CellInstanceFilter. Call prepare_distribcells at simulation

initialization, not program initialization

include/openmc/tallies/filter_cell_instance.h

@@ -51,8 +51,8 @@ public:
   //----------------------------------------------------------------------------
   // Constructors, destructors
 
-  //CellInstanceFilter() = default;
-  //CellInstanceFilter(gsl::span<CellInstance> instances);
+  CellInstanceFilter() = default;
+  CellInstanceFilter(gsl::span<CellInstance> instances);
   ~CellInstanceFilter() = default;
 
   //----------------------------------------------------------------------------

src/geometry_aux.cpp

@@ -320,6 +320,8 @@ find_root_universe()
 void
 prepare_distribcell()
 {
+  write_message("Preparing distributed cell instances...", 5);
+
   // Find all cells listed in a DistribcellFilter or CellInstanceFilter
   std::unordered_set<int32_t> distribcells;
   for (auto& filt : model::tally_filters) {
@@ -395,7 +397,7 @@ prepare_distribcell()
   for (int map = 0; map < target_univ_ids.size(); map++) {
     auto target_univ_id = target_univ_ids[map];
     for (const auto& univ : model::universes) {
-      int32_t offset {0};  // TODO: is this a bug?  It matches F90 implementation.
+      int32_t offset = 0;
       for (int32_t cell_indx : univ->cells_) {
         Cell& c = *model::cells[cell_indx];
 

src/initialize.cpp

@@ -269,9 +269,6 @@ void read_input_xml()
 
   read_tallies_xml();
 
-  // Initialize distribcell_filters
-  prepare_distribcell();
-
   if (settings::run_mode == RUN_MODE_PLOTTING) {
     // Read plots.xml if it exists
     read_plots_xml();

src/simulation.cpp

@@ -5,6 +5,7 @@
 #include "openmc/container_util.h"
 #include "openmc/eigenvalue.h"
 #include "openmc/error.h"
+#include "openmc/geometry_aux.h"
 #include "openmc/material.h"
 #include "openmc/message_passing.h"
 #include "openmc/nuclide.h"
@@ -57,6 +58,9 @@ int openmc_simulation_init()
   // Skip if simulation has already been initialized
   if (simulation::initialized) return 0;
 
+  // Initialize distribcell_filters
+  prepare_distribcell();
+
   // Determine how much work each process should do
   calculate_work();
 

src/tallies/filter_cell_instance.cpp

@@ -9,6 +9,11 @@
 
 namespace openmc {
 
+CellInstanceFilter::CellInstanceFilter(gsl::span<CellInstance> instances)
+{
+  this->set_cell_instances(instances);
+}
+
 void
 CellInstanceFilter::from_xml(pugi::xml_node node)
 {