Forcebalance

Minor changes

In the previous version, the newly merged Drude codes caused ForceBalance to crash when using the SMIRNOFF force field. This is now fixed.

The Gromacs version has been pinned in the GitHub Actions CI (though most Gromacs tests are still skipped because there is no double precision builds as of now).

molecule.py now uses importlib when available, in an ongoing effort to reduce the number of warnings when running tests.

- This release adds support for `openff-recharge`, a new target for fitting charges and bond charge corrections developed by Simon Boothroyd as part of Open Force Field. (see https://github.com/openforcefield/openff-recharge)

- A new example calculation has been added under `studies/025_openff_recharge`.

- The `abinitio` target has been refactored to simplify the different ways in which MM energies can be fitted to QM energies. A new option has been added `energy_mode` where the possible values are

`average` : Subtract out the mean gap (default).
`qm_minimum` : Reference all MM and QM energies to the structure with minimum QM energy.
`absolute` : Use absolute energies in fitting, do not subtract out any energy gap.

When `qm_minimum` is selected for `energy_mode`, negative values of (MM-QM) energy can be given greater weight using the `asymmetry` option.

This release provides compatibility with the Open Force Field Toolkit (OFFTK) v0.7.0, and breaks compatibility with earlier versions. The README has been updated with conda-forge installation instructions.

54 Minor changes

- Fix setup.py to raise an error when numpy and scipy cannot be imported.