atom scattering potential calculation fails when atom name is more than 1 letter

[pcbve1]

In template_iterator.py, in the BaseTemplateIterator class, in the function get_template_scattering potential, there is an issue with the get_a_param function call

MOSAICS/src/mosaics/template_iterator.py

Lines 346 to 364 in 1b8e188

	def get_template_scattering_potential(
	self, atom_idxs: torch.Tensor | np.ndarray = None
	) -> float:
	"""Get the mass (in amu) of a template structure given atom indexes."""
	if atom_idxs is None:
	atom_idxs = np.arange(len(self.structure_df))
	if isinstance(atom_idxs, torch.Tensor):
	atom_idxs = atom_idxs.numpy()
	total_scattering_potential = 0
	atom_counts = self.structure_df.iloc[atom_idxs]["element"].value_counts()
	for atom, count in atom_counts.items():
	atom = atom.upper()
	potentials = get_a_param(atom)
	potentials = torch.sum(potentials).item()
	total_scattering_potential += potentials * count
	return total_scattering_potential

because this function takes a list of atoms as input, passing a multi-character string (for example, the string "Mg" meaning magnesium) will have the simulator get the scattering parameter for M and then g, neither of which are atoms name.

a simple fix that I have implemented in my fork is turning the atom name into a length-1 list
potentials = get_a_param([atom])