diff --git a/integrators/tps2.py b/integrators/tps2.py
index 56cc1add2f8875c002de1a788cc8a15cc3e5a970..729281b055d999cd5da4cb4c0d769d5bfcb265ed 100644
--- a/integrators/tps2.py
+++ b/integrators/tps2.py
@@ -258,6 +258,12 @@ class TPS2(_tpsx.TPSX, \
     print("itnr = ", itnr, "; Err = ", itError)
 
 
+#------------------------------------------------------------------------------#
+
+
+  def _ComputeRHS(self): pass
+
+
 #------------------------------------------------------------------------------#
 
 
diff --git a/integrators/tps2ab.py b/integrators/tps2ab.py
index 44a14437b0bd015fb18ac72bdb5785116a18feb0..7aa4c7d031a496682d59309fc9f487a6051aaeab 100644
--- a/integrators/tps2ab.py
+++ b/integrators/tps2ab.py
@@ -114,6 +114,9 @@ class TPS2AB(tps2.TPS2, _forms.lf_old.LinearForms_Old):
 
 #------------------------------------------------------------------------------#
 
+  def _ComputeRHS(self):
+    from . import _tpsx
+    _tpsx.TPSX._ComputeRHS(self)
 
   def _Compute_v(self):
     import scipy.sparse.linalg