Replace lib.Material.density property with get_density method

openmc/lib/material.py

@@ -87,8 +87,6 @@ class Material(_FortranObjectWithID):
         ID of the material
     nuclides : list of str
         List of nuclides in the material
-    density : float
-        Density of the material in [g/cm^3]
     densities : numpy.ndarray
         Array of densities in atom/b-cm
     name : str
@@ -176,15 +174,6 @@ class Material(_FortranObjectWithID):
         return self._get_densities()[0]
         return nuclides
 
-    @property
-    def density(self):
-      density = c_double()
-      try:
-          _dll.openmc_material_get_density(self._index, density)
-      except OpenMCError:
-          return None
-      return density.value
-
     @property
     def densities(self):
         return self._get_densities()[1]
@@ -226,6 +215,32 @@ class Material(_FortranObjectWithID):
         """
         _dll.openmc_material_add_nuclide(self._index, name.encode(), density)
 
+    def get_density(self, units='atom/b-cm'):
+        """Get density of a material.
+
+        Parameters
+        ----------
+        units : {'atom/b-cm', 'g/cm3'}
+            Units for density
+
+        Returns
+        -------
+        float
+            Density in requested units
+
+        """
+        if units == 'atom/b-cm':
+            return self.densities.sum()
+        elif units == 'g/cm3':
+            density = c_double()
+            try:
+                _dll.openmc_material_get_density(self._index, density)
+            except OpenMCError:
+                return None
+            return density.value
+        else:
+            raise ValueError("Units must be 'atom/b-cm' or 'g/cm3'")
+
     def set_density(self, density, units='atom/b-cm'):
         """Set density of a material.
 

tests/unit_tests/test_lib.py

@@ -1,4 +1,5 @@
 from collections.abc import Mapping
+from ctypes import ArgumentError
 import os
 
 import numpy as np
@@ -186,7 +187,7 @@ def test_material(lib_init):
     assert sum(m.densities) == pytest.approx(rho)
 
     m.set_density(0.1, 'g/cm3')
-    assert m.density == pytest.approx(0.1)
+    assert m.get_density('g/cm3') == pytest.approx(0.1)
     assert m.name == "Hot borated water"
     m.name = "Not hot borated water"
     assert m.name == "Not hot borated water"
@@ -194,16 +195,20 @@ def test_material(lib_init):
 
 def test_properties_density(lib_init):
     m = openmc.lib.materials[1]
-    orig_density = m.density
+    orig_density = m.get_density('atom/b-cm')
+    orig_density_gpcc = m.get_density('g/cm3')
 
     # Export properties and change density
     openmc.lib.export_properties('properties.h5')
-    m.set_density(orig_density*2, 'g/cm3')
-    assert m.density == pytest.approx(orig_density*2)
+    m.set_density(orig_density_gpcc*2, 'g/cm3')
+    assert m.get_density() == pytest.approx(orig_density*2)
 
     # Import properties and check that density was restored
     openmc.lib.import_properties('properties.h5')
-    assert m.density == pytest.approx(orig_density)
+    assert m.get_density() == pytest.approx(orig_density)
+
+    with pytest.raises(ValueError):
+        m.get_density('🥏')
 
 
 def test_material_add_nuclide(lib_init):