diff --git a/examples/simple-dg.py b/examples/simple-dg.py
index 84bea31a4..94adbb3ce 100644
--- a/examples/simple-dg.py
+++ b/examples/simple-dg.py
@@ -275,15 +275,19 @@ def get_local_face_mass_matrix(self, afgrp, volgrp, dtype):
 
         import modepy as mp
         shape = mp.Simplex(volgrp.dim)
-        unit_vertices = mp.unit_vertices_for_shape(shape).T
 
         for face in mp.faces_for_shape(shape):
-            face_vertices = unit_vertices[np.array(face.volume_vertex_indices)].T
-            matrix[:, face.face_index, :] = mp.nodal_face_mass_matrix(
+            from modepy import basis_for_space, quadrature_for_space, PN, Simplex
+            face_space = PN(volgrp.dim - 1, volgrp.order)
+            face_shape = Simplex(volgrp.dim-1)
+            face_quad = quadrature_for_space(face_space, face_shape)
+            face_basis = basis_for_space(face_space, face_shape)
+
+            matrix[:, face.face_index, :] = mp.nodal_mass_matrix_for_face(
+                    face, face_quad,
+                    face_basis.functions,
                     volgrp.basis_obj().functions,
-                    volgrp.unit_nodes, afgrp.unit_nodes,
-                    volgrp.order,
-                    face_vertices)
+                    volgrp.unit_nodes, afgrp.unit_nodes)
 
         actx = self._setup_actx
         return actx.freeze(actx.from_numpy(matrix))
diff --git a/meshmode/array_context.py b/meshmode/array_context.py
index 3a5d53056..6a421ce6c 100644
--- a/meshmode/array_context.py
+++ b/meshmode/array_context.py
@@ -53,7 +53,7 @@
                                          DiscretizationEntityAxisTag)
 from dataclasses import dataclass
 
-from pyrsistent import pmap
+from immutabledict import immutabledict
 logger = logging.getLogger(__name__)
 
 
@@ -781,7 +781,6 @@ class NotAnFEMEinsumError(ValueError):
 
 @memoize_on_first_arg
 def _get_redn_iname_to_insns(kernel):
-    from immutables import Map
     redn_iname_to_insns = {iname: set()
                            for iname in kernel.all_inames()}
 
@@ -789,7 +788,7 @@ def _get_redn_iname_to_insns(kernel):
         for redn_iname in insn.reduction_inames():
             redn_iname_to_insns[redn_iname].add(insn.id)
 
-    return Map({k: frozenset(v)
+    return immutabledict({k: frozenset(v)
                 for k, v in redn_iname_to_insns.items()})
 
 
@@ -1072,7 +1071,7 @@ def _get_iel_to_idofs(kernel):
             raise NotImplementedError(f"Cannot fit loop nest '{insn.within_inames}'"
                                       " into known set of loop-nest patterns.")
 
-    return pmap({iel: frozenset(idofs)
+    return immutabledict({iel: frozenset(idofs)
                  for iel, idofs in iel_to_idofs.items()})