[Pw_forum] vc-relax with BFGS

[Srijan Kumar Saha]

  Dear Gabriele,

  Thanks a lot for your quick response.

  > First, why do you post you request within an existing thread that has
nothing to do with your problem? <

  Sorry, for this mistake. It was an oversight on my side.

  > Where is the proof that the final symmetry is different from the initial
one? <

  Here goes more direct proof:

  Initial symmetry :  48 Sym.Ops. (with inversion).
  Final symmetry :  6 Sym.Ops. (no inversion).

 >  I think that you should not pay attention to differences of the order of
10^-9, <

If we compare the final & initial positions given in my previous email,
then we can see that
the differences are quite large. These differences go away if we use
Wentzcovitch Damped Dynamics, instead of BFGS. However, Damped Dynamics
stops
without convergence (50 iterations completed, stopping). Since this dynamics
converge very
slowly, I would like to know whether VC-RELAX with BFGS has the above
capability of respecting the
symmetry.

Thanks & regards,
Srijan K.
CCMT
Indian Institute of Science
India 560012
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