Lennard Jones wall pressure


I have a question about the pressure that LAMMPS calculate with : https://lammps.sandia.gov/doc/compute_pressure.html

For a confined system with 2 lennard jones wall . the pressure that LAMMPS calculate is the pressure that is just between molecules or it is P_molecules + P_wall/molecule ?

Thanks for your attention.

If by LJ wall you mean a plane of frozen atoms,
then yes, interactions between mobile and wall
atoms are included in the pressure. If you
mean a flat, idealized wall, like from fix wall/lj93,
then the fix doc page mentions there is a fix modify viral yes/no
option to include (or not) the wall/particle interactions
in the pressure calculation. But even if you don’t
the compressed particles interact with each
other and should thus be at a “pressure” that is consistent
with the pressure produced by the wall.