Virial Stress

Dear All,

I just want to know is the virial calculation of stress, the true stress or engineering stress? i meant following command in LAMMPS compute true stress * Volume or engineering stress * Volume?

compute 1 all stress/atom

fix 1 all ave/atom 1 100 100 c_1[3]

compute 2 all reduce sum f_1


The doc page explains exactly what it is computing.
Compare that to your definition of “true” or “engineerging”