[lammps-users] Strain for elastic constants

Hello all,

In one of the examples which calculates elastic constants (examples/ELASTIC/), the change in strain in x direction is computed as:

change_box all x delta 0 {delta} xy delta {deltaxy} xz delta ${deltaxz} remap units box

my question is, why do we need to change xy and xz? Isn’t depsilon_xx = dlx/lx0 ? If yes, then changing xhi with x delta 0 ${delta} should be enough for getting dlx and hence depsilon_xx.

Please let me know if more clarification is needed.

Thanks,
Jamal