[Pw_forum] about convergence criterion in supercell

[lfhuang at theory.issp.ac.cn]

Dear all friends:
  I have a question on convergence criterion in supercell, which is:

     For unit cell, I define "conv_thr" and "tr2_ph" to be 1*d-12 and
     1*d-14,respectively. Then I take a 4*4*4 supercell, and is it
     precise enough to define 4*4*4*d-12 and 4*4*4d-14 for "conv_thr"
     and "tr2_ph" respectively? If it is not, what is the reason?

Thanks a lot for your time to read my letter!
And I would like greatly appreciate the one who can give me some resonable
rationale!

Best Wishes!