1from ase.data import atomic_numbers, reference_states, chemical_symbols 

2 

3 

4def get_element_info(symbol, latticeconstant): 

5 if isinstance(symbol, str): 

6 atomic_number = atomic_numbers[symbol] 

7 else: 

8 atomic_number = symbol 

9 symbol = chemical_symbols[atomic_number] 

10 

11 if latticeconstant is None: 

12 if reference_states[atomic_number]['symmetry'] in ['fcc', 'bcc', 'sc']: 

13 lattice_constant = reference_states[atomic_number]['a'] 

14 else: 

15 raise NotImplementedError( 

16 ("Cannot guess lattice constant of a %s element." % 

17 (reference_states[atomic_number]['symmetry'],))) 

18 else: 

19 if isinstance(latticeconstant, (int, float)): 

20 lattice_constant = latticeconstant 

21 else: 

22 raise ValueError("Lattice constant must be of type int or float.") 

23 

24 return symbol, atomic_number, lattice_constant