Dear Gulp users,

I am relatively new to the field and I would like to apologise in advance in case my question is trivial.

I am interested in crystal structure relaxation methods and I am struggling to understand some procedures regarding the derivation of the optimised structure. I am aware that ion positions inside the unit cell are obtained using the derivatives of the energy potential function with respect to the positions and lattice vectors are scaled using the strain tensor. However, I am not familiar with how the strain tensor is derived. Are the lattice vectors updated each time the ion positions are changed?

Thank you in advance.

Sincerely,

Antonia