[lammps-users] Question on group- different in serial and parallel

Hello lammps users,
I am trying to study crack tip opening using fix and setforce on a group
of atoms. I use the group command as 'group r1 id <=300' to select
atoms an which the fix is applied. This works well when run in serial.
In parallel the atoms of group r1 are not the atoms initially numbered
1-300. This is probably because of renumbering during parallel running
of code. Is there a way around this problem. Thank you



Define the group in a different way - e.g. use a geometric
region to bound it. The group doc explains all the
ways a group can be defined.