Troubles with change_box

Hi all:

I am trying to deform my simulation box, which is a Y2O3-ZrO2 bicrystal, by using the “change_box” command. I do not want to change the volume, so I used the following line:

change_box all y scale 1.02 z volume z scale 0.98

It actually changes the Ly and Lz length as specified, but does not keep the volume constant. I tried also:

change_box all x scale 1.1 z volume

(an example taken from the LAMMPS site), but it changes the volume as well.

I am running the latest LAMMPS version (April 20, 2012) made with the "USER-EWALDN” package. My script follows:

lattice custom 20.520 a1 1 0 0 a2 0 1.1855 0 a3 0 0 6.326 basis 0 0 0
read_restart restart.sigma5.mobility
kspace_style ewald/n 1.0e-4

change_box all x scale 1.1 z volume
#or change_box all y scale 1.02 z volume z scale 0.98

#Output settings, fixes, etc…

I am also attaching the restart file, just in case it may be needed. Any help, please? Thank you in advance

Juanjo

Juan J. Meléndez
Associate Professor
Department of Physics · University of Extremadura
Avda. de Elvas, s/n 06006 Badajoz (Spain)
Phone: +34 924 28 96 55
Fax: +34 924 28 96 51
Email: melendez@…1779…
Web: http://materiales.unex.es/miembros/personal/jj-melendez/Index.html

restart.sigma5.mobility (259 KB)

juan,

you have run into a bug in the code for the change_box command.

i am looking into it right now.

more later,
     axel.

juan,

as it turns out, there were multiple bugs.
please find attached a patch that corrects
them or use the attached source file to
replace the corresponding file in your tree.
let us know, if there are still any problems.

good luck,
    axel.

change_box.cpp.gz (3.44 KB)

lammps-change-box-fix.diff.gz (777 Bytes)

posted this as a patch - see if you
agree with the changes Axel - I did
it a bit differently.

Thanks,
Steve