diff --git a/src/dmrg/mps.hpp b/src/dmrg/mps.hpp
index c6e5753b..3a27cecc 100644
--- a/src/dmrg/mps.hpp
+++ b/src/dmrg/mps.hpp
@@ -667,9 +667,9 @@ template <typename S> struct MPSInfo {
     }
     ubond_t get_max_bond_dimension() const {
         total_bond_t max_bdim = 0;
-        for (int i = 0; i <= n_sites; i++)
+        for (int i = 0; i < n_sites; i++)
             max_bdim = max(left_dims[i]->n_states_total, max_bdim);
-        for (int i = n_sites; i >= 0; i--)
+        for (int i = n_sites; i > 0; i--)
             max_bdim = max(right_dims[i]->n_states_total, max_bdim);
         return (ubond_t)min((uint64_t)max_bdim,
                             (uint64_t)numeric_limits<ubond_t>::max());