Add API warning for AbsoluteAlchemicalFactory.replace_reaction_field
@@ -889,6 +889,10 @@ class AbsoluteAlchemicalFactory(object):
def replace_reaction_field(self, reference_system):
"""Replace reaction-field electrostatics with Custom*Force terms to ensure c_rf = 0.
+ .. warning:: Unstable API.
+ This method is still experimental. It could be moved in some
+ other module or have its signature changed in the near future.
+
A deep copy of the system is made.
If reaction field electrostatics is in use, this will add a CustomNonbondedForce and CustomBondForce to the System
