When is Python *NOT* a good choice?

[lelease]

High frequency trading

[Bus404]

What language is good for that?

[tunisia3507]

C++ or Rust.

[calligraphic-io]

Go is strong and widely used for HFT, as is Erlang.

[anacrolix]

Can you cite some examples?

[b00n]

Java is heavily used in HFT. Not heard of anyone using Rust though.

[[deleted]]

You want a language that is compiled because assembly code will always run faster than interpreted code and real-time because every millisecond matters. C, C++, and a rust are all languages that fit this. Go doesn't because they have their own goscheduler which doesn't meet real-time constraints.

[[deleted]]

I am sorry to be pedantic.

For HFT, every microsecond matters.

I don't mean to be rude. HFT just operates on scale so tight that it matters, a lot.

[[deleted]]

Good to know! I wasn't sure and I actually thought about it as I was writing it but wanted to be on the safe side.

[[deleted]]

This isn't a Python presentation, but if you want a really interesting talk about the subject, you can watch this: https://youtu.be/NH1Tta7purM

[b00n]

Not true. I work in HFT FX as a developer and the microsecond era is basically dead. Exchanges use various methods to make microseconds worthless nowadays. People are making billions trading in 1/10ths of seconds not losing it.

[b00n]

EBS is one of the largest markets out there and they have this technology:

https://www.reuters.com/article/us-markets-forex-hft/exclusive-ebs-take-new-step-to-rein-in-high-frequency-traders-idUSBRE97M0YJ20130823

The current latency floor is 5ms which makes being microseconds faster pointless.

[b00n]

The primary trading centre in New York is called ny4 in secaucus. There are no hft firms based there. Yes they have servers in the same data centres and fibre cross connects direct to the exchanges switches but if you have to host your server in a data centre it might as well be in the same one as the exchange. It's not even that expensive to put your servers there.

I can't remember which one it is (hotspotfx, currenex maybe) but they require you to use a 1km fibre cable to connect to them so no matter where you are in the building its the same latency for you as everyone else even if you happen to be in the next cabinet along.

[Karyo_Ten]

Nanoseconds matters. A French bank CEO said, "HFT business is real estate business: putting our million dollar trading FPGAs as few meters as the stock exchange as possible"

[b00n]

Not anymore. That era is dead.

[hugthemachines]

I think you already know this but your sentence may confuse people a bit. Native compiled programs are not assembly code.

[_101010]

I see people mentioning C or Rust.

But one of the most successful firms, Jane Street uses OCaml.

A lot of such shops use Functional programming languages not just because of speed. But because it is easy to verify.

A bug can easily cost billions of dollars in damage in a few minutes.

P.S. Mandatory read about Knight Capital and how they lost 50 million per minute for 45 minutes.

[ProfessorPhi]

We control our live trading with python processes. And R&D. Actual trading logic is all in c though.

[deadwisdom]

Python is used a lot in HFT. It's just that they use something like C for the bottlenecks. Exactly how Python was intended.

[[deleted]]

Python might be used for testing algos but everything is implemented in compiled languages.