Convert particle track writing to C++

src/track_output.cpp

@@ -0,0 +1,80 @@
+#include "openmc/track_output.h"
+
+#include "openmc/constants.h"
+#include "openmc/hdf5_interface.h"
+#include "openmc/position.h"
+#include "openmc/settings.h"
+#include "openmc/simulation.h"
+
+#include "xtensor/xtensor.hpp"
+
+#include <cstddef> // for size_t
+#include <sstream>
+#include <string>
+#include <vector>
+
+namespace openmc {
+
+//==============================================================================
+// Global variables
+//==============================================================================
+
+// Forward declaration needed in order to declare tracks as threadprivate
+extern std::vector<std::vector<Position>> tracks;
+#pragma omp threadprivate(tracks)
+
+std::vector<std::vector<Position>> tracks;
+
+//==============================================================================
+// Non-member functions
+//==============================================================================
+
+void add_particle_track()
+{
+  tracks.emplace_back();
+}
+
+void write_particle_track(const Particle& p)
+{
+  tracks.back().push_back({p.coord[0].xyz});
+}
+
+void finalize_particle_track(const Particle& p)
+{
+  std::stringstream filename;
+  filename << settings::path_output << "track_" << simulation::current_batch
+    << '_' << simulation::current_gen << '_' << p.id << ".h5";
+
+  // Determine number of coordinates for each particle
+  std::vector<int> n_coords;
+  for (auto& coords : tracks) {
+    n_coords.push_back(coords.size());
+  }
+
+  #pragma omp critical (FinalizeParticleTrack)
+  {
+    hid_t file_id = file_open(filename.str().c_str(), 'w');
+    write_attribute(file_id, "filetype", "track");
+    write_attribute(file_id, "version", VERSION_TRACK);
+    write_attribute(file_id, "n_particles", tracks.size());
+    write_attribute(file_id, "n_coords", n_coords);
+    for (int i = 1; i <= tracks.size(); ++i) {
+      const auto& t {tracks[i-1]};
+      size_t n = t.size();
+      xt::xtensor<double, 2> data({n,3});
+      for (int j = 0; j < n; ++j) {
+        data(j, 0) = t[j].x;
+        data(j, 1) = t[j].y;
+        data(j, 2) = t[j].z;
+      }
+      std::string name = "coordinates_" + std::to_string(i);
+      write_dataset(file_id, name.c_str(), data);
+    }
+    file_close(file_id);
+  }
+
+  // Clear particle tracks
+  tracks.clear();
+}
+
+} // namespace openmc