Hi,I am doing the NPT ensemble dynamics in discover module, and giving the system which is a 3D periodic boundary system a stress in the xx direction. In this process,I want to keep the bc lengths fixed and only see the a deformation. I have done it through "constraints->lattice->fix length->tick b,c",however,the bc lengths still change after NPT ensemble dynamics.Is there anything wrong with my job? Thanks a lot.

Wendy