Agreements

Basic

pip install --no-deps --editable .

Get

n_atoms is always an integer even when there is no topological info.
n_structures is None when the form has no structural info. If the form can store structures n_structures is always an integer (0, if there are no structures in the form).
if time, box, etc... (structural attributes) are not present in an object... the output is a list with as many Nones as structure_indices.

Iterator

Coordinates is always a numpy.ndarray with shape (n_frames, n_atoms, 3), even with n_frames=1.
Box is always a numpy.ndarray with shape (n_frames, 3, 3), even with n_frames=1.

Form

Structural Iterator

Coordinates is always a numpy.ndarray with shape (n_frames, n_atoms, 3), even with n_frames=1.
Box is always a numpy.ndarray with shape (n_frames, 3, 3), even with n_frames=1.

Native

if time, box, etc... (structural attributes) are not present in an object... the output is a list with as many Nones as structures in the object. if there are no structures... all attributes are equal to None.