Remove references to _volum_discr

Author: thomasgibson

grudge/discretization.py

@@ -244,7 +244,7 @@ def _has_affine_groups(self):
         return any(
                 megrp.is_affine
                 and issubclass(megrp._modepy_shape_cls, Simplex)
-                for megrp in self._volume_discr.mesh.groups)
+                for megrp in self._mesh.groups)
 
     @memoize_method
     def _base_to_geoderiv_connection(self, dd: DOFDesc):
@@ -443,7 +443,7 @@ def _discr_tag_volume_discr(self, discretization_tag):
 
         # Refuse to re-make the volume discretization
         if discretization_tag is DISCR_TAG_BASE:
-            return self._volume_discr
+            return self.discr_from_dd("vol")
 
         from meshmode.discretization import Discretization
         return Discretization(