TLDR on Making Repo Pip Installable

[raunakdoesdev]

I tried digging through the setup.py file and some other aspects of the repo to try and understand how it is able to pip install so cleanly with Pytorch as a dependency

I'm struggling with this in my own project, so would appreciate any insight from project maintainers. The main problem I run into is that I cannot include torch as an "install_requires" dependency as this ends up installing a cpu version by default. I really like how lightning does it, where if torch is already installed it respects that dependency and if it is not then it installs a cpu version by default.