@@ -2025,7 +2025,7 @@ class _VectorizedFinalizedBuilderMixin(_FinalizedBuilderMixin):

             "elements at once using 'hamiltonian_term'.",

             KwantDeprecationWarning

         )

-        site_offsets = np.cumsum([0] + [len(s) for s in self.site_arrays])

+        site_offsets, _, _ = self.site_ranges.transpose()

         if i == j:

             which_term = self._onsite_term_by_site_id[i]

             (w, _), (off, _) = self.subgraphs[self.terms[which_term].subgraph]

@@ -321,10 +321,10 @@ def random_hopping_integral(rng):

 def check_onsite(fsyst, sites, subset=False, check_values=True):

-    vectorized = isinstance(fsyst, (system.FiniteVectorizedSystem, system.InfiniteVectorizedSystem))

+    vectorized = system.is_vectorized(fsyst)

     if vectorized:

-        site_offsets = np.cumsum([0] + [len(s) for s in fsyst.site_arrays])

+        site_offsets, _, _ = fsyst.site_ranges.transpose()

     freq = {}

     for node in range(fsyst.graph.num_nodes):

@@ -353,10 +353,10 @@ def check_onsite(fsyst, sites, subset=False, check_values=True):

 def check_hoppings(fsyst, hops):

-    vectorized = isinstance(fsyst, (system.FiniteVectorizedSystem, system.InfiniteVectorizedSystem))

+    vectorized = system.is_vectorized(fsyst)

     if vectorized:

-        site_offsets = np.cumsum([0] + [len(s) for s in fsyst.site_arrays])

+        site_offsets, _, _ = fsyst.site_ranges.transpose()

     assert fsyst.graph.num_edges == 2 * len(hops)

     for edge_id, edge in enumerate(fsyst.graph):