# shear examples

Dear all,
Could you please explain shear problems in examples folder

1. fix nve + fix temp/rescale was used to relax the system in 3 directions.
2. velocity is assigned to atoms in boundary - frozen part A fixed velocity and mobile group changed velocity with respect to position
Then, they unfixed fix temp/rescale and reassigned it in 2 (y,z) directions, but fix nve is still available in 3 directions
Does nve time integration influence on assigned velocity in x direction in mobile group (non-frozen part) at this moment?
Ha.

Fix nve is applied to all 3 dimensions of the atoms in
the group it is defined for.

Steve

Dear all,
Could you please explain shear problems in examples folder
1. fix nve + fix temp/rescale was used to relax the system in 3 directions.
2. velocity is assigned to atoms in boundary - frozen part A fixed velocity
and mobile group changed velocity with respect to position
Then, they unfixed fix temp/rescale and reassigned it in 2 (y,z) directions,
but fix nve is still available in 3 directions
Does nve time integration influence on assigned velocity in x direction in
mobile group (non-frozen part) at this moment?

no. fix nve does not modify velocities for atoms where the forces are set
to zero and that is what fix setforce does. note that it operates on the
upper *and* lower boundaries. so the boundary atoms need to follow
newton's first law of motion only.

axel.