[Pw_forum] Constraints

[yuva rani]

   Thanks for your suggestion about ecutwfc and ecutrho. I had another
doubt to share with you.
   I had relaxed two layers of aluminium atoms consisting of 112
atoms. Now, I want to stack a molecule on its surface. Inorder to
relax this, I need to use constraints. So please give me the
suggestion of using Constraint_cards and how to fix the parameters.
Also give me the example input file using constraints. Thanks in
advance.