Better use of ParticleType in tracks.py

paulromano · Feb 3, 2026 · Jan 23, 2026 · Jan 23, 2026 · Jan 27, 2026 · Jan 27, 2026
commit 4310612d5613a2d6dab95227e6f73d4827f42223
diff --git a/docs/source/usersguide/settings.rst b/docs/source/usersguide/settings.rst
@@ -400,7 +400,7 @@ below.
     {
       openmc::SourceSite particle;
       // weight
-      particle.particle = openmc::PDG_NEUTRON;
+      particle.particle = openmc::ParticleType::neutron();
       particle.wgt = 1.0;
       // position
       double angle = 2.0 * M_PI * openmc::prn(seed);
@@ -477,7 +477,7 @@ parameters to the source class when it is created:
     {
       openmc::SourceSite particle;
       // weight
-      particle.particle = openmc::PDG_NEUTRON;
+      particle.particle = openmc::ParticleType::neutron();
       particle.wgt = 1.0;
       // position
       particle.r.x = 0.0;

@@ -132,6 +132,9 @@
 _dll.openmc_new_filter.argtypes = [c_char_p, POINTER(c_int32)]
 _dll.openmc_new_filter.restype = c_int
 _dll.openmc_new_filter.errcheck = _error_handler
+_dll.openmc_particle_filter_get_bins.argtypes = [c_int32, POINTER(c_int32)]
+_dll.openmc_particle_filter_get_bins.restype = c_int
+_dll.openmc_particle_filter_get_bins.errcheck = _error_handler
 _dll.openmc_spatial_legendre_filter_get_order.argtypes = [c_int32, POINTER(c_int)]
 _dll.openmc_spatial_legendre_filter_get_order.restype = c_int
 _dll.openmc_spatial_legendre_filter_get_order.errcheck = _error_handler

diff --git a/openmc/source.py b/openmc/source.py
@@ -20,12 +20,10 @@
 from openmc.stats.univariate import Univariate
 from ._xml import get_elem_list, get_text
 from .mesh import MeshBase, StructuredMesh, UnstructuredMesh
+from .statepoint import _VERSION_STATEPOINT
 from .utility_funcs import input_path
 
 
-_VERSION_STATEPOINT = 18
-
-
 class SourceBase(ABC):
     """Base class for external sources
 

diff --git a/openmc/tracks.py b/openmc/tracks.py
@@ -15,7 +15,7 @@
 Parameters
 ----------
 particle : openmc.ParticleType
-    Type of the particle (PDG-backed)
+    Type of the particle
 states : numpy.ndarray
     Structured array containing each state of the particle. The structured array
     contains the following fields: ``r`` (position; each direction in [cm]),
@@ -25,7 +25,7 @@
 
 """
 def _particle_track_repr(self):
-    return f"<ParticleTrack: {self.particle}, {len(self.states)} states>"
+    return f"<ParticleTrack: {str(self.particle)}, {len(self.states)} states>"
 ParticleTrack.__repr__ = _particle_track_repr
 
 
@@ -93,7 +93,7 @@ def filter(self, particle=None, state_filter=None):
         Parameters
         ----------
         particle : str or int or openmc.ParticleType
-            Matching particle type (alias, PDG, or GNDS nuclide)
+            Matching particle type (name, PDG number, or type)
         state_filter : function
             Function that takes a state (structured datatype) and returns a bool
             depending on some criteria.
@@ -123,22 +123,10 @@ def filter(self, particle=None, state_filter=None):
 
         """
         matching = []
-        particle_match = None
-        if particle is not None:
-            try:
-                if isinstance(particle, str):
-                    particle_match = ParticleType(particle)
-                else:
-                    particle_match = ParticleType(particle)
-            except (TypeError, ValueError):
-                track = type(self).__new__(type(self))
-                track.identifier = self.identifier
-                track.particle_tracks = []
-                return track
         for t in self:
             # Check for matching particle
-            if particle_match is not None:
-                if t.particle != particle_match:
+            if particle is not None:
+                if t.particle != ParticleType(particle):
                     continue
 
             # Apply arbitrary state filter

diff --git a/tests/unit_tests/test_tracks.py b/tests/unit_tests/test_tracks.py
@@ -140,8 +140,10 @@ def test_filter(sphere_model, run_in_tmpdir):
     assert matches == tracks
     matches = tracks.filter(state_filter=lambda s: s['E'] > 0.0)
     assert matches == tracks
-    matches = tracks.filter(particle='bunnytron')
+    matches = tracks.filter(particle='proton')
     assert matches == []
+    with pytest.raises(ValueError):
+        tracks.filter(particle='bunnytron')
 
 
 def test_write_to_vtk(sphere_model):