Cannot find openff.units while loading the molecule class.

[subhamoymahajan]

Describe the bug The package fails to load Molecule class from openff.toolkit.topology

To Reproduce from openff.toolkit.topology import Molecule

Output Traceback (most recent call last): File "/lustre/eaglefs/scratch/subhamoy/FFgen/test.py", line 1, in from openff.toolkit.topology import Molecule File "/home/subhamoy/.conda-envs/FFgen/lib/python3.12/site-packages/openff_toolkit-0.14.4+12.g575501a2-py3.12.egg/openff/toolkit/topology/init.py", line 1, in from openff.toolkit.topology.molecule import ( File "/home/subhamoy/.conda-envs/FFgen/lib/python3.12/site-packages/openff_toolkit-0.14.4+12.g575501a2-py3.12.egg/openff/toolkit/topology/molecule.py", line 54, in from openff.units import Quantity, unit ModuleNotFoundError: No module named 'openff.units'

Computing environment (please complete the following information):

• Operating system: Linux
• Output of running conda list

  Name Version Build Channel

  _libgcc_mutex 0.1 conda_forge conda-forge _openmp_mutex 4.5 2_gnu conda-forge babel 2.13.1 pypi_0 pypi bzip2 1.0.8 hd590300_5 conda-forge ca-certificates 2023.7.22 hbcca054_0 conda-forge contourpy 1.2.0 pypi_0 pypi cycler 0.12.1 pypi_0 pypi fonttools 4.44.0 pypi_0 pypi kiwisolver 1.4.5 pypi_0 pypi ld_impl_linux-64 2.40 h41732ed_0 conda-forge libexpat 2.5.0 hcb278e6_1 conda-forge libffi 3.4.2 h7f98852_5 conda-forge libgcc-ng 13.2.0 h807b86a_2 conda-forge libgomp 13.2.0 h807b86a_2 conda-forge libnsl 2.0.1 hd590300_0 conda-forge libsqlite 3.44.0 h2797004_0 conda-forge libuuid 2.38.1 h0b41bf4_0 conda-forge libzlib 1.2.13 hd590300_5 conda-forge matplotlib 3.8.1 pypi_0 pypi ncurses 6.4 h59595ed_2 conda-forge networkx 3.2.1 pypi_0 pypi numpy 1.26.1 pypi_0 pypi openff-toolkit 0.14.4+12.g575501a2 pypi_0 pypi openmmforcefields 0.12.0+4.g637d551 pypi_0 pypi openssl 3.1.4 hd590300_0 conda-forge packaging 23.2 pypi_0 pypi pillow 10.1.0 pypi_0 pypi pip 23.3.1 pyhd8ed1ab_0 conda-forge pyparsing 3.1.1 pypi_0 pypi python 3.12.0 hab00c5b_0_cpython conda-forge python-dateutil 2.8.2 pypi_0 pypi readline 8.2 h8228510_1 conda-forge scipy 1.11.3 pypi_0 pypi setuptools 68.2.2 pyhd8ed1ab_0 conda-forge six 1.16.0 pypi_0 pypi tk 8.6.13 noxft_h4845f30_101 conda-forge tzdata 2023c h71feb2d_0 conda-forge wheel 0.41.3 pyhd8ed1ab_0 conda-forge xz 5.2.6 h166bdaf_0 conda-forge

Additional context I have used the main branch.

[mattwthompson]

How did you install the toolkit? You're missing most dependencies, so I doubt you installed the conda package. Here's how we recommend installing a fresh environment, and

$ mamba install openff-toolkit -c conda-forge

usually works into an existing environment.

[subhamoymahajan]

I was unable to install it using conda, so I used git clone and python setup.py install to install openff-toolkit.

I think the problem would still persists because openff.units is not defined. Is a specific version of openff-toolkit working for you that I can test ?

[subhamoymahajan]

In openff/toolkit/topology/molecule.py line 60,

from openff.toolkit.utils.constants import DEFAULT_AROMATICITY_MODEL . Correspondingly, constants.py exists at openff/toolkit/utils. However, for line 54,

from openff.units import Quantity, unit, openff has no file named units.py. So i feel installing an older version where the file still exists would work.

[mattwthompson]

Please use the documented installation methods I linked above; local installations do not bring in dependencies and is not supported due to the extra, unnecessary dependency management burden that is passed on to users.

[subhamoymahajan]

Mamba installation worked for me. Thanks.