[Pw_forum] A few questions about MD simulations

Paolo Giannozzi paolo.giannozzi at uniud.it
Sat Jun 1 15:49:34 CEST 2013

On Fri, 2013-05-31 at 12:49 -0400, Robert Hembree wrote:

>  I noticed that upon completion of the simulation that the
> wavefunction files seem to have disappeared.

wavefunctions do not "disappear", but only those at the last step
(or the last two, or three, if wavefunctionn interpolation is used)
are kept

> Is there an easy way to access this information? Or would it require
> large changes to the code base?

it would require a lot of disk space. It should be relatively easy 
to modify the code in such a way that it saves all wavefunctions. 
Please look into the code that performs wavefunction interpolation,
"update_wfc", for inspiration. Or, you can do the simulation one 
step at the time, save wavefunction files under a different name.

> Third: In the source files where does the MD simulation start? For
> example, an scf cycle is handled in the file electrons.f90. 

look into "move_ions.f90". The MD code is unfortunately very confusing.

> is the correct way to access the planewave expansion coefficients
> through the 
> USE wavefunctions_module, ONLY : psic

no. Wavefunctions are contained in variable evc(i,j), i=plane-wave
index, j=band index


Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222 

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