[Pw_forum] new unit-cell volume in variable cell relaxation

[Eduardo Ariel Menendez Proupin]

Hi,
When doing variable cell relaxation it is useful to have the current volume
of the variable cell. This is reported in the output when
cell_dynamics='damp-w', e.g. in a line as the following
 new unit-cell volume =   3705.0385 (a.u.)^3

However, when cell_dynamics='bfgs' the cell volume is not reported (pw.x of
version 4.0.4 ).

I see in the text that bfgs is still experimental. If interesting for
debuging the code, I can supply an input  case where the relaxation fails .
In this case, in the 3rd bfgs step,

   WARNING: integrated charge=   140.52433035, expected=   288.00000000

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     from electrons : error #         1
     charge is wrong

I suspect the bgfs made drastic change and the electronic calculation went
crazy. With damped dynamics it works smoothly.

Best regards

-- 
Eduardo Menendez
Departamento de Fisica
Facultad de Ciencias
Universidad de Chile
Phone: (56)(2)9787439
URL: http://fisica.ciencias.uchile.cl/~emenendez
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