Normally "switch languages" isn't great advice, but in this case I think it's worth considering. I have heard people coming from Django and Rails background describe Elixir as "a love child between python and ruby". Personally I love it
Not to the same degree that Python does (then again no other general-purpose language does!), but it does have the start of one and it's fairly cohesive.
Fortran? R? C? C++? Even Java may occasionally make a good showing here (depending on what you are doing).
Having seen... things... unless it's written by people with the right skillset (and with funding and the right environment), that it exists doesn't mean you should use it (and the phrase "it's a trap" comes to mind sadly). https://scicomp.stackexchange.com/a/10923/1437 applies (and note I still wouldn't call Julia mainstream yet), so while I'm not saying people shouldn't try, the phrase "don't roll your own crypto" applies just as much to the numeric and scientific computing fields.
You can split it off and have your Python code be an API you call, but now you have at least two languages involved (Python+Elixir, plus JS somewhere, plus the possible mix of C/C++/Fortran/Rust(maybe?)). Given Ruby on Rails was mentioned, just using Django seems similarly like the least risky thing to do (this all assumes you are doing numerical stuff, not just a standard CRUD app).
I'm not super tuned into the scientific computing ecosystem, so not sure if this is what you mean. But maybe? Elixir's Numerical Elixir projects seem very relevant for scientific computing. Check 'em out: https://github.com/elixir-nx
Edit: Hah! aloha2436 beat me to the answer. Sorry for the repetition.
