I did this in VASP but I guess this would be the case for any program. I have a structure that has a cubic conventional cell (a = 9.86 A). I found the primitive cell (a=b=c=6.97, alpha=90, beta=60, gamma=120) and used that as the input structure.
I relaxed the structure and that results in changes in the cell (a=7.23,b=6.97,c=7.2,alpha=90.99,beta=58.1,gamma=121).
Isn't the cubic symmetry now broken because the lattice parameters and angles have all changed? How do I go from the relaxed primitive cell back to the conventional cubic cell??
Edit: Initial CIF file (conventional cell), as well as the input POSCAR (primitive cell) and output CONTCAR files are here: https://github.com/DoubleKx/arg_example
Edit2: I'm trying to replicate the examples from this paper. I'm on Part 1. I've found the primitive cell, enumerated the structure, and run a relaxation (on just one of the enumerated structures).