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Comment by SatvikBeri | Hacker News Reader

We've quietly been using Julia at our hedge fund for ~4 years. It has saved us a lot of money.

The syntax is easy for Math-heavy Researchers who might not have as much software engineering experience to use, but it's much faster than numpy, which we used for 5 years before.

The package management is sane – not as good as Rust, but way better than Python/Javascript.

We have one non-trivial macro which makes our codebase ~15% shorter, and would be hard to emulate in a lot of other languages.

The REPL is really good, second only to Clojure IMO.

The main thing I want to see more of is "static Julia", e.g. better support for static type-checking and binaries, and fortunately that seems to be where the language is going!

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I am curious, have you run into any of the issues with Julia discussed here [0] (also discussed on HN [1])? Those problems would seem particularly troubling at a hedge fund to me, if you have to question the accuracy of your results after chaining multiple complex models together. Curious about your stance on / experience with correctness issues in Julia.

[0] https://yuri.is/not-julia/

[1] https://news.ycombinator.com/item?id=31396861

We've run into issues with Arrow – it or its dependencies would frequently break on updates, and we stopped using it. But none of the other issues mentioned in the article have ever come up for us. In particular, a lot of the problems come from using OffsetArrays.jl, which is a library designed to let you use different starting indices for an array, which we just don't use.

It's worth noting that we initially migrated ~15kloc of numpy data/numeric pipelines to Julia, and mostly found the same values, with the exception of something that turned out to be a bug in a Python library.

I would say that the biggest Julia annoyance we've run into has to do with the way the Expr type is implemented, particularly the fact that it's mutable, which makes some of the metaprogramming we want to do substantially harder. But that's not a bug per se, just a design choice I don't like.

I won't pretend that Julia doesn't have its fair share of `wats`, but in my experience they tend to be in one of two categories

* usage of `OffsetArrays.jl` (really, just avoiding this package fixes most of the issues)

* hideously cursed syntax that should only pass a code review if your name is Lovecraft, but for some reason the parser allows it

if you don't do either of those things (which at least personally speaking, I don't) then I don't think the rate of "correctness issues" is any higher or lower than I experience in other ecosystems. In fact, it's probably lower

Don't forget that other languages are not immune... I love the `polars` library as well but in my two years of using it I've encountered organically two separate "correctness" bugs. It's just par for the course for any big code surface

Adding to the list is the tragedy of Julia programming language's type system: https://medium.com/@393069484/a-tragedy-of-julias-type-syste...

there exist many high quality criticisms of Julia's type system, but this article does not contain them if I'm being totally honest. I think this writeup here https://viralinstruction.com/posts/badjulia/#the_type_system... contains more valid gripes about the type system than the one you linked.

Using Union as an example is more understandable than using abstract types. I can also explain why abstract types are broken, but that would involve a complex interaction of subtyping and abstract interpretation.

In addition, I believe that abstract types are not that horrible since in industry we use OOP any way (https://github.com/Suzhou-Tongyuan/ObjectOriented.jl). I coworked with the author of this package several years ago. Currently, he is developping a different branch of Julia compiler. Since OOP makes eveything easier to design (from linter to static compiler), and programmers prefer OOP over abstract types, I personally don't think they will cause huge problems.

> We've quietly been using Julia at our hedge fund…

This! I’ve found a lot of value in Julia for math specially in financial analysis.

Julia’s DataFrame and general development workflow are excellent for research and when it comes to deployment is not too shabby either.

I’m aware of pandas and the rest in Python, but for some reason Julia feels a lot more “ergonomic” for my use case.

Financial economist and Julia aficionado here looking to transition to academia to industry if you're ever hiring. If you have any feedback /tips it would be much appreciated. Email and website in bio.

Also a financial economist and Julia lover -- it's a fantastic tool for finance IMO

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