[ase-users] RuntimeError: Atoms object has no calculator.

[Roger Mason]

Hello,

This example, from https://wiki.fysik.dtu.dk/ase/ase/atom.html, fails:

Python 2.7.13 (default, Jul  2 2017, 01:20:25) 
[GCC 4.2.1 Compatible FreeBSD Clang 3.4.1 (tags/RELEASE_34/dot1-final 208032)] on freebsd10
Type "help", "copyright", "credits" or "license" for more information.
>>> from ase import Atoms
>>> OH = Atoms('OH')
>>> OH[0].charge = -1
>>> OH.get_charges()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/rmason/Software/ASE/ase/ase/atoms.py", line 639, in get_charges
    raise RuntimeError('Atoms object has no calculator.')
RuntimeError: Atoms object has no calculator.

ase --version
ase-3.15.0

What must I do to make it work?

Thanks,
Roger