[Pw_forum] [EXTERNAL] Re: How to reuse cell geometry for successive straining of a lattice

[Zimmerman, Jonathan A]

Thank you Axel, I will give your first suggestion a try and let you know
if I need the elaborate option.

Many thanks and regards,

Jon
----------------------------------
Jonathan A. Zimmerman
Principal Member of Technical Staff
Mechanics of Materials Department
Sandia National Laboratories
P.O. Box 969 - MS 9957
Livermore, CA 94551

Tel: (925) 294-2437 or (800) 4SANDIA x4-2437
Fax: (925) 294-2355
E-mail: jzimmer at sandia.gov
------------------------------------------





On 1/23/14 2:14 PM, "Axel Kohlmeyer" <akohlmey at gmail.com> wrote:

>On Wed, Jan 22, 2014 at 9:06 PM, Zimmerman, Jonathan A
><jzimmer at sandia.gov> wrote:
>> Hi Pw_forum folks,
>
>hi jon,
>
>> I'm new to Quantum Espresso, but I have checked the archives and I don't
>> think this question has been asked (at least not this way). Here goes:
>>
>> I'd like to perform a series of vc-relax calculations on a crystal
>>lattice
>> such that each time I increase the amount of applied strain in a given
>> direction (via the CELL_PARAMETERS), from one calculation to the next I
>> reuse the other, unconstrained CELL_PARAMETERS and the ATOMIC_POSITIONS.
>> This way, my Poisson contraction and non-uniform relaxation of the
>>atoms is
>> done gently, rather than restarting each calculation with the same
>> 'unrelaxed' ATOMIC_POSITIONS. I'm hoping that a few of you have done
>> something similar and have a script or suggestions for carrying-over the
>> CELL_PARAMETERS (those I'm not fixing) and ATOMIC_POSITIONS from one
>> calculation to the next. If so, please respond.
>
>since nobody else responded to your question here are a few thoughts on
>that:
>
>what you want to do should be easily doable with a little bit of
>scripting. i suggest you have a look at the pwo2xsf.sh script that can
>be used to extract coordinates from a QE run into an .xsf file, which
>contains coordinates and cell vectors. similarly, there is xsf2pwi.sh,
>that would convert a set of .xsf coordinates to a format suitable for
>input of pw.x. if you write a little script to process a given input
>file template, then you can combine these two scripts with your script
>and do the processing as you intend to do.
>
>it might also be possible to combine this.
>
>another, more elaborate, option would be to adopt the new "COUPLE"
>interface that allows to interface pw.x in a (superficially) similar
>fashion as you know it from LAMMPS. so you could make it run a
>repeated relaxation output the final coordinates, modify, and
>continue. this code is only available through the svn currently. but
>if you want to go this route, please contact me off-list and i'd be
>more than happy to collaborate with you to write a little "driver" for
>your needs.
>
>best regards from philly,
>
>    axel.
>
>>
>> Thanks!
>>
>> Jon Zimmerman
>> ----------------------------------
>> Jonathan A. Zimmerman
>> Sandia National Laboratories
>> E-mail: jzimmer at sandia.gov
>> ------------------------------------------
>>
>>
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>
>
>
>-- 
>Dr. Axel Kohlmeyer  akohlmey at gmail.com  http://goo.gl/1wk0
>College of Science & Technology, Temple University, Philadelphia PA, USA
>International Centre for Theoretical Physics, Trieste. Italy.
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