Fix collision track feature for photon transport

docs/source/io_formats/collision_track.rst

@@ -10,7 +10,7 @@ may also be written after each batch when multiple files are requested
 (``collision_track.N.h5``) or when the run is performed in parallel. The file
 contains the information needed to reconstruct each recorded collision.
 
-The current revision of the collision track file format is 1.1.
+The current revision of the collision track file format is 1.2.
 
 **/**
 
@@ -33,7 +33,7 @@ The current revision of the collision track file format is 1.1.
               - ``event_mt`` (*int*) -- ENDF MT number identifying the reaction.
               - ``delayed_group`` (*int*) -- Delayed neutron group index (non-zero for delayed events).
               - ``cell_id`` (*int*) -- ID of the cell in which the collision occurred.
-              - ``nuclide_id`` (*int*) -- ZA identifier of the nuclide (ZZZAAAM format).
+              - ``nuclide_id`` (*int*) -- PDG number of the nuclide (100ZZZAAAM).
               - ``material_id`` (*int*) -- ID of the material containing the collision site.
               - ``universe_id`` (*int*) -- ID of the universe containing the collision site.
               - ``n_collision`` (*int*) -- Collision counter for the particle history.

docs/source/io_formats/settings.rst

@@ -98,6 +98,11 @@ sub-elements:
     A list of strings representing the nuclide, to define specific
     define specific target nuclide collisions to be banked.
 
+    .. note::
+      Electron and positron collision-track events are not associated with
+      a specific nuclide. If a ``nuclides`` entry is specified, these events
+      are omitted.
+
     *Default*: None
 
   :reactions:
@@ -606,30 +611,30 @@ found in the :ref:`random ray user guide <random_ray>`.
     *Default*: None
 
   :adjoint_source:
-    Specifies an adjoint fixed source for adjoint transport simulations, and 
-    follows the format for :ref:`source_element`. The distributions which make 
-    up the adjoint source are subject to the same restrictions as forward 
+    Specifies an adjoint fixed source for adjoint transport simulations, and
+    follows the format for :ref:`source_element`. The distributions which make
+    up the adjoint source are subject to the same restrictions as forward
     fixed sources in Random Ray mode.
 
     *Default*: None
-  
+
   :adjoint:
-    Specifies whether to perform adjoint transport. The default is 'False', 
+    Specifies whether to perform adjoint transport. The default is 'False',
     corresponding to forward transport.
 
     *Default*: None
-  
+
   :volume_estimator:
-    Specifies choice of volume estimator for the random ray solver. Options 
+    Specifies choice of volume estimator for the random ray solver. Options
     are 'naive', 'simulation_averaged', or 'hybrid'. The default is 'hybrid'.
 
     *Default*: None
 
   :volume_normalized_flux_tallies:
-    Specifies whether to normalize flux tallies by volume (bool). The 
-    default is 'False'. When enabled, flux tallies will be reported in units 
-    of cm/cm^3. When disabled, flux tallies will be reported in units of cm 
-    (i.e., total distance traveled by neutrons in the spatial tally 
+    Specifies whether to normalize flux tallies by volume (bool). The
+    default is 'False'. When enabled, flux tallies will be reported in units
+    of cm/cm^3. When disabled, flux tallies will be reported in units of cm
+    (i.e., total distance traveled by neutrons in the spatial tally
     region).
 
     *Default*: None
@@ -1757,11 +1762,11 @@ mesh-based weight windows.
         The ratio of the lower to upper weight window bounds.
 
         *Default*: 5.0
-    
+
     For FW-CADIS:
 
       :targets:
-        A sequence of IDs corresponding to the tallies which cover phase 
+        A sequence of IDs corresponding to the tallies which cover phase
         space regions of interest for local variance reduction.
 
         *Default*: None

docs/source/usersguide/settings.rst

@@ -792,6 +792,11 @@ collision_track.h5 file at the end of the simulation. The file contains
 300 recorded collisions that occurred in materials with IDs 1 or 2, involving
 fission or (n,2n) reactions on the nuclides U-238 or O-16, within cells
 with IDs 5 and 12.
+
+.. note::
+   Electron and positron collision-track events are not associated with a
+   specific nuclide. If a ``nuclides`` entry is specified, these events are omitted.
+
 The file can be read using :func:`openmc.read_collision_track_file`.
 The example below shows how to extract the data from the collision_track
 feature and displays the fields stored in the file:

include/openmc/constants.h

@@ -35,7 +35,7 @@ constexpr array<int, 2> VERSION_VOXEL {2, 0};
 constexpr array<int, 2> VERSION_MGXS_LIBRARY {1, 0};
 constexpr array<int, 2> VERSION_PROPERTIES {1, 1};
 constexpr array<int, 2> VERSION_WEIGHT_WINDOWS {1, 0};
-constexpr array<int, 2> VERSION_COLLISION_TRACK {1, 1};
+constexpr array<int, 2> VERSION_COLLISION_TRACK {1, 2};
 
 // ============================================================================
 // ADJUSTABLE PARAMETERS

include/openmc/nuclide.h

@@ -84,6 +84,9 @@ class Nuclide {
   double collapse_rate(int MT, double temperature, span<const double> energy,
     span<const double> flux) const;
 
+  //! Return a ParticleType object representing this nuclide
+  ParticleType particle_type() const { return {Z_, A_, metastable_}; }
+
   //============================================================================
   // Data members
   std::string name_; //!< Name of nuclide, e.g. "U235"

src/collision_track.cpp

@@ -200,8 +200,13 @@ void collision_track_record(Particle& particle)
     return;
 
   int cell_id = model::cells[cell_index]->id_;
-  const auto* nuclide_ptr = data::nuclides[particle.event_nuclide()].get();
-  std::string nuclide = nuclide_ptr->name_;
+  std::string nuclide {};
+  int nuclide_id = 0;
+  if (particle.event_nuclide() != NUCLIDE_NONE) {
+    const auto* nuclide_ptr = data::nuclides[particle.event_nuclide()].get();
+    nuclide = nuclide_ptr->name_;
+    nuclide_id = nuclide_ptr->particle_type().pdg_number();
+  }
   int universe_id = model::universes[particle.lowest_coord().universe()]->id_;
   double delta_E = particle.E_last() - particle.E();
   int material_index = particle.material();
@@ -224,8 +229,7 @@ void collision_track_record(Particle& particle)
   site.event_mt = particle.event_mt();
   site.delayed_group = particle.delayed_group();
   site.cell_id = cell_id;
-  site.nuclide_id =
-    10000 * nuclide_ptr->Z_ + 10 * nuclide_ptr->A_ + nuclide_ptr->metastable_;
+  site.nuclide_id = nuclide_id;
   site.material_id = material_id;
   site.universe_id = universe_id;
   site.n_collision = particle.n_collision();

tests/regression_tests/collision_track/case_1_Reactions/inputs_true.dat

@@ -51,7 +51,7 @@
     </source>
     <collision_track>
       <reactions>(n,fission) 101</reactions>
-      <max_collisions>300</max_collisions>
+      <max_collisions>30</max_collisions>
     </collision_track>
     <seed>1</seed>
   </settings>

tests/regression_tests/collision_track/case_2_Cell_ID/inputs_true.dat

@@ -51,7 +51,7 @@
     </source>
     <collision_track>
       <cell_ids>22</cell_ids>
-      <max_collisions>300</max_collisions>
+      <max_collisions>30</max_collisions>
     </collision_track>
     <seed>1</seed>
   </settings>

tests/regression_tests/collision_track/case_3_Material_ID/inputs_true.dat

@@ -51,7 +51,7 @@
     </source>
     <collision_track>
       <material_ids>1</material_ids>
-      <max_collisions>300</max_collisions>
+      <max_collisions>30</max_collisions>
     </collision_track>
     <seed>1</seed>
   </settings>

tests/regression_tests/collision_track/case_4_Nuclide_ID/inputs_true.dat

@@ -51,7 +51,7 @@
     </source>
     <collision_track>
       <nuclides>O16 U235</nuclides>
-      <max_collisions>300</max_collisions>
+      <max_collisions>30</max_collisions>
     </collision_track>
     <seed>1</seed>
   </settings>

tests/regression_tests/collision_track/case_5_Universe_ID/inputs_true.dat

@@ -52,7 +52,7 @@
     <collision_track>
       <cell_ids>22</cell_ids>
       <universe_ids>77</universe_ids>
-      <max_collisions>300</max_collisions>
+      <max_collisions>30</max_collisions>
     </collision_track>
     <seed>1</seed>
   </settings>

tests/regression_tests/collision_track/case_6_deposited_energy_threshold/inputs_true.dat

@@ -51,7 +51,7 @@
     </source>
     <collision_track>
       <deposited_E_threshold>550000.0</deposited_E_threshold>
-      <max_collisions>300</max_collisions>
+      <max_collisions>30</max_collisions>
     </collision_track>
     <seed>1</seed>
   </settings>

tests/regression_tests/collision_track/case_7_all_parameters_used_together/inputs_true.dat

@@ -56,7 +56,7 @@
       <material_ids>1 11</material_ids>
       <nuclides>U238 U235 H1 U234</nuclides>
       <deposited_E_threshold>100000.0</deposited_E_threshold>
-      <max_collisions>300</max_collisions>
+      <max_collisions>30</max_collisions>
     </collision_track>
     <seed>1</seed>
   </settings>

tests/regression_tests/collision_track/test.py

@@ -59,28 +59,13 @@
 
 """
 
-import os
-
 import openmc
-import openmc.lib
 import pytest
 
 from tests.testing_harness import CollisionTrackTestHarness
 from tests.regression_tests import config
 
 
-@pytest.fixture(scope="function")
-def two_threads(monkeypatch):
-    """Set the number of OMP threads to 2 for the test."""
-    monkeypatch.setenv("OMP_NUM_THREADS", "2")
-
-
-@pytest.fixture(scope="function")
-def single_process(monkeypatch):
-    """Set the number of MPI process to 1 for the test."""
-    monkeypatch.setitem(config, "mpi_np", "1")
-
-
 @pytest.fixture(scope="module")
 def model_1():
     """Cylindrical core contained in a first box which is contained in a larger box.
@@ -203,19 +188,19 @@ def model_1():
 
 @pytest.mark.parametrize(
     "folder, model_name, parameter",
-    [("case_1_Reactions", "model_1", {"max_collisions": 300, "reactions": ["(n,fission)", 101]}),
+    [("case_1_Reactions", "model_1", {"max_collisions": 30, "reactions": ["(n,fission)", 101]}),
         ("case_2_Cell_ID", "model_1", {
-         "max_collisions": 300, "cell_ids": [22]}),
+         "max_collisions": 30, "cell_ids": [22]}),
         ("case_3_Material_ID", "model_1", {
-         "max_collisions": 300, "material_ids": [1]}),
+         "max_collisions": 30, "material_ids": [1]}),
         ("case_4_Nuclide_ID", "model_1", {
-         "max_collisions": 300, "nuclides": ["O16", "U235"]}),
+         "max_collisions": 30, "nuclides": ["O16", "U235"]}),
         ("case_5_Universe_ID", "model_1", {
-         "max_collisions": 300, "cell_ids": [22], "universe_ids": [77]}),
+         "max_collisions": 30, "cell_ids": [22], "universe_ids": [77]}),
         ("case_6_deposited_energy_threshold", "model_1", {
-         "max_collisions": 300, "deposited_E_threshold": 5.5e5}),
+         "max_collisions": 30, "deposited_E_threshold": 5.5e5}),
         ("case_7_all_parameters_used_together", "model_1", {
-            "max_collisions": 300,
+            "max_collisions": 30,
             "reactions": ["elastic", 18, "(n,disappear)"],
             "material_ids": [1, 11],
             "universe_ids": [77],
@@ -235,21 +220,3 @@ def test_collision_track_several_cases(
         "statepoint.5.h5", model=model, workdir=folder
     )
     harness.main()
-
-
-@pytest.mark.skipif(config["event"], reason="Results from history-based mode.")
-def test_collision_track_2threads(model_1, two_threads, single_process):
-    # This test checks that the `max_collisions` setting is honored:
-    # no collisions beyond the specified limit should be recorded.
-    #
-    # For the result to be reproducible, the number of threads and
-    # the transport mode (history vs. event) must remain fixed.
-    assert os.environ["OMP_NUM_THREADS"] == "2"
-    assert config["mpi_np"] == "1"
-    model_1.settings.collision_track = {
-        "max_collisions": 200
-    }
-    harness = CollisionTrackTestHarness(
-        "statepoint.5.h5", model=model_1, workdir="case_8_2threads"
-    )
-    harness.main()