Pxx component of pressure tensor is not similar with "compute stress/atom" and "thermo_style pxx"?

LAMMPS LAMMPS Beginners
1

Hi everybody,

I computed pxx component of pressure tensor simply with calling pxx as
variable pxx equal pxx
and therefore printed at thermo_style command.

However, I don’t get similar results for pxx component of pressure tensor with the following command:

compute press waterbox stress/atom NULL
compute ptensor waterbox reduce sum c_press[1]

I also attached my input and data files as well as outputs for more details. As you can see pxx is too different with these two procedures.

Thanks for your fruitful commands,

config.data (1.6 MB)
config2.in (3.7 KB)
output.txt (9.3 KB)

2

In LAMMPS stress != pressure.

Please reread the documentation of compute stress/atom with more care.