[lammps-users] Querries regarding minimization

Hi all,

I am getting some strange results with minimize command.

With spp boundaries, when I run minimize, I sometimes see that the box length in x dimension (and the volume) changes even though the manual says that volume change is not permitted in ‘minimize’. An example log file ‘vol_minimize_log.lammps’ is attached where volume changes after 20 time steps. Another strange thing is that the lx values reported in the last step of minimization and the first step of following run with ‘fix deform’ (in y) are different.

What could be the reason for these?



vol_minimize_log.lammps (7.42 KB)

If you have a "s" boundary, then you have a free surface. When
you minimize, there is nothing stopping atoms at the surface from
moving in/out and changing the effective box size in that dimension,
since the box size is just the bounding box on the atoms for "s".

I'll have to look at why lx changed between the end of minimization
and the start of the next run.