Dependencies:
- Python3.0+ (recommended: Python3.5+)
- Cython0.21+ (recommended: Cython0.21)
- Numpy1.8.0+ (recommended: Numpy1.8.0)
- Scipy0.31.2+ (recommended: Scipy0.16)
Optional:
- GAMESS (for generating force fields by numerical differentiation)

PyVCI has not been developed or tested for ARM processors (M1/M2 chips).
To install PyVCI on newer Macs, a virtual conda environment may be set
up to emulate intel chips and provide access to earlier python versions:

CONDA_SUBDIR=osx-64 conda create -n rosetta python=3.5 
conda activate rosetta
python -c "import platform;print(platform.machine())"
conda config --env --set subdir osx-64      # make sure that conda commands in this environment use intel packages