The only thing I'd recommend is exposing "eval()" or something to let users tell you when they want you to evaluate things. It'll save a ton of time when it comes to hot-fixing performance and memory use issues. It's really hard to determine when to evaluate, and although it's a fun problem to figure out, it's nice to have an escape hatch for users to just tell you. (Flashlight has explored this and written about it here: https://fl.readthedocs.io/en/latest/debugging.html?highlight...)

If you're interested, I've looked into symbolic laziness, which allows you to infer correct input sizes even when the constraints happen later. Can be useful for errors. https://dev-discuss.pytorch.org/t/loop-tools-lazy-frontend-e...