diff --git a/pyblock2/driver/readwfn.py b/pyblock2/driver/readwfn.py
index 0d8c3d3b..74d75af7 100755
--- a/pyblock2/driver/readwfn.py
+++ b/pyblock2/driver/readwfn.py
@@ -24,7 +24,7 @@
 if len(sys.argv) > 1:
     arg_dic = {}
     for i in range(1, len(sys.argv)):
-        if sys.argv[i] in ['-su2', '-sz', '-expect', '-reduntant']:
+        if sys.argv[i] in ['-su2', '-sz', '-expect', '-redundant']:
             arg_dic[sys.argv[i][1:]] = ''
         elif sys.argv[i].startswith('-'):
             arg_dic[sys.argv[i][1:]] = sys.argv[i + 1]
@@ -36,7 +36,7 @@
             (A) python readwfn.py -config dmrg.conf -out ./out
             (B) python readwfn.py dmrg.conf
             (C) python readwfn.py dmrg.conf -expect
-            (D) python readwfn.py dmrg.conf -reduntant
+            (D) python readwfn.py dmrg.conf -redundant
             (E) python readwfn.py -integral FCIDUMP -prefix ./scratch -dot 2 -su2
             (F) python readwfn.py -integral FCIDUMP -prefix ./scratch -dot 2 -sz
             (G) python readwfn.py ... -sym c1
@@ -46,9 +46,9 @@
             out: dir for storing block2 MPS
             expect: if given, the energy expectation value of MPS
                 is calculated using block2 and printed at the end
-            reduntant: if given, the reduntant parameter in the
+            redundant: if given, the redundant parameter in the
                 StackBlock MPS will be retained.
-                Note that removing reduntant parameters do not
+                Note that removing redundant parameters do not
                 affect quality of MPS.
 
             when no config file is given/available:
@@ -79,7 +79,7 @@
 hf_occ = None
 out_dir = "./out"
 expect = "expect" in arg_dic
-redunt = "reduntant" in arg_dic
+redunt = "redundant" in arg_dic
 mps_tags = ["KET"]
 if "config" in arg_dic:
     config = arg_dic["config"]
@@ -285,12 +285,10 @@ def swap_order_left(idx):
     l, m, r = mps_info.left_dims[idx], hamil.basis[idx], mps_info.left_dims[idx + 1]
     clm = StateInfo.get_connection_info(l, m, r)
     for ik in range(r.n):
-        bbed = clm.n if ik == r.n - 1 else clm.n_states[ik + 1]
         dx = []
         g = 0
-        for bb in range(clm.n_states[ik], bbed):
-            ibba = clm.quanta[bb].data >> 16
-            ibbb = clm.quanta[bb].data & 0xFFFF
+        for bb in range(clm.acc_n_states[ik], clm.acc_n_states[ik + 1]):
+            ibba, ibbb = clm.ij_indices[bb]
             nx = l.n_states[ibba] * m.n_states[ibbb]
             dx.append((l.quanta[ibba], m.quanta[ibbb], g, g + nx))
             g += nx
@@ -310,12 +308,10 @@ def swap_order_right(idx):
     l, m, r = mps_info.right_dims[idx], hamil.basis[idx], mps_info.right_dims[idx + 1]
     clm = StateInfo.get_connection_info(m, r, l)
     for ik in range(l.n):
-        bbed = clm.n if ik == l.n - 1 else clm.n_states[ik + 1]
         dx = []
         g = 0
-        for bb in range(clm.n_states[ik], bbed):
-            ibba = clm.quanta[bb].data >> 16
-            ibbb = clm.quanta[bb].data & 0xFFFF
+        for bb in range(clm.acc_n_states[ik], clm.acc_n_states[ik + 1]):
+            ibba, ibbb = clm.ij_indices[bb]
             nx = m.n_states[ibba] * r.n_states[ibbb]
             dx.append((m.quanta[ibba], r.quanta[ibbb], g, g + nx))
             g += nx
diff --git a/pyblock2/driver/writewfn.py b/pyblock2/driver/writewfn.py
index 3e0c6dad..8c89d3c9 100755
--- a/pyblock2/driver/writewfn.py
+++ b/pyblock2/driver/writewfn.py
@@ -264,12 +264,10 @@ def swap_order_left(idx):
     l, m, r = mps.info.left_dims[idx], hamil.basis[idx], mps.info.left_dims[idx + 1]
     clm = B2StateInfo.get_connection_info(l, m, r)
     for ik in range(r.n):
-        bbed = clm.n if ik == r.n - 1 else clm.n_states[ik + 1]
         dx = []
         g = 0
-        for bb in range(clm.n_states[ik], bbed):
-            ibba = clm.quanta[bb].data >> 16
-            ibbb = clm.quanta[bb].data & 0xFFFF
+        for bb in range(clm.acc_n_states[ik], clm.acc_n_states[ik + 1]):
+            ibba, ibbb = clm.ij_indices[bb]
             nx = l.n_states[ibba] * m.n_states[ibbb]
             dx.append((l.quanta[ibba], m.quanta[ibbb], g, g + nx))
             g += nx
@@ -289,12 +287,10 @@ def swap_order_right(idx):
     l, m, r = mps.info.right_dims[idx], hamil.basis[idx], mps.info.right_dims[idx + 1]
     clm = B2StateInfo.get_connection_info(m, r, l)
     for ik in range(l.n):
-        bbed = clm.n if ik == l.n - 1 else clm.n_states[ik + 1]
         dx = []
         g = 0
-        for bb in range(clm.n_states[ik], bbed):
-            ibba = clm.quanta[bb].data >> 16
-            ibbb = clm.quanta[bb].data & 0xFFFF
+        for bb in range(clm.acc_n_states[ik], clm.acc_n_states[ik + 1]):
+            ibba, ibbb = clm.ij_indices[bb]
             nx = m.n_states[ibba] * r.n_states[ibbb]
             dx.append((m.quanta[ibba], r.quanta[ibbb], g, g + nx))
             g += nx