diff --git a/grudge/execution.py b/grudge/execution.py
index 546ef1659965bfe85b76a8ad2daa9a3a8144fbcc..59af300fbdf5aa25ba4ad3c0517daf05be2dec97 100644
--- a/grudge/execution.py
+++ b/grudge/execution.py
@@ -532,8 +532,9 @@ class ExecutionMapper(mappers.Evaluator,
                 matrices_ary_dev = self.bound_op.operator_data_cache[cache_key]
             except KeyError:
                 matrices = repr_op.matrices(out_grp, in_grp)
-                matrices_ary = np.empty((
-                    noperators, out_grp.nunit_dofs, in_grp.nunit_dofs), dtype=field.entry_dtype)
+                matrices_ary = np.empty(
+                    (noperators, out_grp.nunit_dofs, in_grp.nunit_dofs),
+                    dtype=field.entry_dtype)
                 for i, op in enumerate(insn.operators):
                     matrices_ary[i] = matrices[op.rst_axis]
                 matrices_ary_dev = self.array_context.from_numpy(matrices_ary)