diff --git a/test/complete_interfaces_test.py b/test/complete_interfaces_test.py index 6a795665..3a59eb55 100644 --- a/test/complete_interfaces_test.py +++ b/test/complete_interfaces_test.py @@ -1,7 +1,7 @@ import importlib import os -from ase.io import read +from ase.io import read, write import mala from mala.common.parameters import ParametersBase import numpy as np @@ -357,3 +357,41 @@ def test_additional_calculation_data_json(self): new_ldos_calculator.atoms.get_positions()[i, j], rtol=accuracy_fine, ) + + def test_atoms_to_lammps_data_multielement(self): + """ + Test if the atoms to LAMMPS interface gives alphabetical ordering. + + If I am not misunderstanding anything than how the element ordering + is transferred from an atoms object to LAMMPS is not necessarily + well-defined. In the current interface, it seems to simply be + alphabetical ordering. We need to check whether this holds. + It could change, and since LAMMPS itself does not name the elements + in its data file, one would not notice. + + Returns + ------- + + """ + vasp_source_file = open("test_element.vasp", mode="w") + vasp_source_file.write( + "O Al Te H\n 1.0000000000000000\n 6.0000000000000000 0.0000000000000000 0.0000000000000000\n 0.0000000000000000 6.0000000000000000 0.0000000000000000\n 0.0000000000000000 0.0000000000000000 6.0000000000000000\nO Al Te H\n 1 1 1 1\nCartesian\n 0.0 0.0 1.0\n 0.0 0.0 2.0\n 0.0 0.0 3.0\n 0.0 0.0 4.0 \n" + ) + vasp_source_file.close() + atoms = read("test_element.vasp", format="vasp") + write("test_element.lammps", atoms, format="lammps-data") + + raw_file = open("test_element.lammps") + lines = raw_file.readlines() + found_atoms = 0 + for idx, line in enumerate(lines): + if "Atoms" in line: + found_atoms = idx + + alphabetical_order_elements = [3, 1, 4, 2] + + for i in range(2, 6): + assert ( + int(lines[found_atoms + i].split()[1]) + == alphabetical_order_elements[i - 2] + )