This might be a reflection of a memory problem. It is known that loading large files into VNL can causes memory issues. To avoid this, one can attempt to putt the eigenstates (the 3D grids) into separate files, or to restart VNL between loading different large files. This is obviously not an ideal solution, but it's a work-around for now, that hopefully can solve the problem.
To recalculate the eigenstates should be very fast, and can easily be done from the checkpoint file, for example using something like
from ATK.KohnSham import *
from ATK.MPI import processIsMaster
# Opening vnlfile
if processIsMaster(): file = VNLFile('TET_1.vnl')
scf = restoreSelfConsistentCalculation ('tet.nc')
eigenstates = calculateEigenstates(
self_consistent_calculation = scf,
quantum_numbers = (33)
)
for state_index,state in enumerate(eigenstates):
label='Eigenstate'+' '+str(state_index)
if processIsMaster(): file.addToSample(state, 'New Molecule', label)