Dear Lammps users,

I compute this four quantities:

compute 1 intertop stress/atom NULL
compute 2 intertop reduce sum c_1[3]
compute 3 intertop group/group interbot
compute 4 intertop reduce sum fz

During minimize process, c_2 does not converge to 0, while c_3 and c_4 do, shouldn't atom stress->0 in the process of energy minimization?

Any help would be appreciated.


Fully converged energy minimization sets the force on each atom and each group of atoms to zero. Hence it makes sense that c_3 is zero, and also c_4. Stress is a little more complicated. If there are no periodic interactions and the total force on each atom is zero, then c_1 will be zero. With periodic interactions, it is possible to have a non-zero c_1. Also, if you the atom velocities are non-zero, their contribution must be excluded using the virial keyword.