compress non-periodic simulation box

Hi all,
I’m a new LAMMPS-user. Could you kindly explain me a question

  1. For my understanding, if I compress (or stretch) a non-periodic simulation box, its volume will be changed such that I cannot use fix nve or fix nvt. Maybe, it doesn’t make perfect sense to compress non-periodic simulation box but I am going to consider initial crack in model.
    However, when I use fix npt, an errors appear like “Cannot use fix nvt/npt/nph on a non-periodic dimension (fix_nh.cpp:315)”
    What would you advise me to do? Any suggestion will be appreciated.

I think this was answered yesterday. You can use fix nvt on a
non-periodic system. You can't use a barostat (e.g. npt or nph)
on non-periodic dimensions.