[lammps-users] question about fix box/relax

LAMMPS LAMMPS Mailing List Mirror
1

Deal lammps users,

I am running energy minimization to obtain a relaxed inherent structure(i.e. I need freely moving boundaries during minimization to have it relaxed). The box/relax option in fix command seems what I am looking for, but I cannot open the description page in the manual and I don't see any implementation of this option in the source code. Is this just a stub? Is it coming soon? or do you think I have other options to get what I want with current lammps? Thanks

ps: I know one solution is to write a script to repeat following steps
1. do minimization with fix box size, calculate pressure or potential energy
2. rescale box size towards a smaller pressure and lower potential energy, do minimization again
until we get zero pressure/lowest potential energy.
But I didn't find a command to simply rescale the box size without actually running the system. Did I miss anything?

Best regards,

YQ

2

The fix box/relax file isn't yet officially in LAMMPS, so it's
just a stub entry in the doc file. Probably in
the next month. Also, we will soon add a fix deform that
will let you shrink/expand/deform the box dynamically. Along
with it will be a command like box_change that lets you
explicityly change the box size/shape, so that will allow you
to do the iterative procedure you outline below.

Steve