Is it possible to do cluster expansion for a system using structures defined by the user? This will be useful in case user already have a database of structures and corresponding total energies.
from the ATAT FAQ:
Q. I already have structures and energies. What if I just want to fit them?
A. You need a lat.in files to specify the geometry of the lattice and you need to create one subdirectory for each structure (name them as you which). In each subdirectory, you need a str.out file to specify the geometry of the structure and an energy file to indicate the energy of that structure. For the format of those files, type maps -h | more. Note that the energy must per unit cell of the structure (not the lattice).