Issue installing on M1 Mac about exoplanet

[joellama]

Thanks @dfm! The trick it seems on M1 is then you get float128 isn't defined, that is get-aroundable by pegging pymc3==3.8. Thanks again!

[dfm]

This isn't an exoplanet or M1 problem really - it's a PyMC3/Theano issue. You should be able to fix it by pinning numpy<1.22, which PyMC3 should do, but doesn't!

[dfm]

You shouldn't need to restrict to Python 3.8. This is now an issue with the conda versions of PyMC3 (only PyMC3 v3.9 is available). Instead of pinning the Python version, you can just run pip install -U pymc3 to get a version of PyMC3 that works with more recent Pythons.

[dfm]

Unfortunately I think that the numpy pin does remain necessary because Theano is no longer maintained.