Add boundary property on Surface

pyproject.toml

@@ -31,7 +31,7 @@ classifiers = [
     "Topic :: Scientific/Engineering",
     "Programming Language :: Python :: 3",
 ]
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 # TODO: add PyMOAB once on PyPI
 dependencies = ["numpy"]
 
@@ -49,4 +49,4 @@ ci = ["pytest-cov"]
 [tool.setuptools_scm]
 
 [tool.setuptools]
-package-dir = {"" = "src"}
+package-dir = {"" = "src"}

src/pydagmc/dagnav.py

@@ -86,7 +86,7 @@ def volumes_by_material(self) -> Dict[str, list[Volume]]:
             A dictionary where keys are material names (str) and values
             are lists of Volume objects.
         """
-        material_map: DefaultDict[str, list[Volume]] = defaultdict(list)
+        material_map: defaultdict[str, list[Volume]] = defaultdict(list)
         for volume in self.volumes:
             if volume.material is None:
                 continue
@@ -347,7 +347,7 @@ def _check_category_and_dimension(self):
             raise ValueError(f"{identifier} has no category or geom_dimension tags assigned.")
 
     def __eq__(self, other):
-        return type(other) == type(self) and \
+        return type(other) is type(self) and \
                self.model == other.model and \
                self.handle == other.handle
 
@@ -403,6 +403,11 @@ def category(self, category: str):
         """Set the DAGMC set's category."""
         self._tag_set_data(self.model.category_tag, category)
 
+    @property
+    def groups(self) -> list[Group]:
+        """Get list of groups containing this DAGMC set."""
+        return [group for group in self.model.groups if self in group]
+
     @abstractmethod
     def _get_triangle_sets(self):
         """Retrieve all (surface) sets under this set that contain triangle elements.
@@ -584,6 +589,34 @@ def reverse_volume(self) -> Optional[Volume]:
     def reverse_volume(self, volume: Volume):
         self.senses = [self.forward_volume, volume]
 
+    @property
+    def _boundary_group(self) -> Optional[Group]:
+        for group in self.groups:
+            if "boundary:" in group.name:
+                return group
+        return None
+
+    @property
+    def boundary(self) -> Optional[str]:
+        """Name of the boundary assigned to this surface."""
+        group = self._boundary_group
+        if group is not None:
+            return group.name.removeprefix('boundary:')
+        return None
+
+    @boundary.setter
+    def boundary(self, name: Optional[str]):
+        group = self._boundary_group
+
+        if group is not None:
+            # Remove surface from existing group
+            group.remove_set(self)
+
+        # create a new group or get an existing group
+        if name is not None:
+            group = Group.create(self.model, name=f"boundary:{name}")
+            group.add_set(self)
+
     @property
     def volumes(self) -> list[Volume]:
         """Get the parent volumes of this surface.
@@ -619,12 +652,7 @@ def __init__(self, model: Model, handle: np.uint64):
         self._check_category_and_dimension()
 
     @property
-    def groups(self) -> list[Group]:
-        """Get list of groups containing this volume."""
-        return [group for group in self.model.groups if self in group]
-
-    @property
-    def _material_group(self):
+    def _material_group(self) -> Optional[Group]:
         for group in self.groups:
             if "mat:" in group.name:
                 return group

test/test_dagnav.py

@@ -917,7 +917,7 @@ def test_surface_sense_value_error_on_wrong_length():
 
     # Create dummy volumes for valid input
     vol1 = model.create_volume(global_id=1)
-    
+
     # Empty list
     with pytest.raises(ValueError, match="Senses should be a list of two volumes."):
         surf.senses = []
@@ -948,6 +948,30 @@ def test_surface_create_invalid_filename():
         model.create_surface(filename='my_model.step')
 
 
+def test_surface_boundary():
+    """Test the boundary property of Surface."""
+    model = pydagmc.Model()
+    surf = model.create_surface(global_id=1)
+
+    # Initially, boundary should be None
+    assert surf.boundary is None
+
+    # Set a valid boundary condition
+    surf.boundary = 'Reflecting'
+    assert surf.boundary == 'Reflecting'
+    assert [1] == sorted(model.groups_by_name['boundary:Reflecting'].surface_ids)
+
+    # Change the boundary condition
+    surf.boundary = 'Vacuum'
+    assert surf.boundary == 'Vacuum'
+    assert [1] == sorted(model.groups_by_name['boundary:Vacuum'].surface_ids)
+    assert [] == sorted(model.groups_by_name['boundary:Reflecting'].surface_ids)
+
+    # Remove the boundary condition by setting it to None
+    surf.boundary = None
+    assert surf.boundary is None
+
+
 def test_geometryset_category_runtime_error(request):
     """Test category returns None when tag is missing."""
     model = pydagmc.Model()