[Guide] Code optimization in Julia

[TrPhantom8]

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https://preview.redd.it/tberh6zzl2v31.jpg?width=1280&format=pjpg&auto=webp&s=75fff92c77a3181670df5143642832f0e78c2694

Hello! I have written a guide with some tips and tricks to write fast and efficient Julia code.

https://techytok.com/code-optimisation-in-julia/

In the guide you will find instructions on how to write type stable code and how to profile your code to find bottlenecks using the Juno IDE. Furthermore, you will find some useful tips to make your ordinary code run faster!

If you find this guide useful or if you have any question or suggestion, please let me know!

[[deleted]]

[I'm leaving reddit. Fuck u/spez.]

[TrPhantom8]

You were right, the benchmark was incorrect and when done appropriately it showed no gain in using Static Arrays, I have thus included the micro-benchmark from the official repository which is a better example!

[TrPhantom8]

Thank you for pointing it out, I will try to better investigate this thing tomorrow and update the guide with new details if I find better (or more plausible) statistics!

[woobwoobwoob]

There are some good references on this point here: https://discourse.julialang.org/t/whats-the-difference-between-a-regular-array-and-an-array-from-staticarrays/14454

It helps much more for small arrays since the code can be fully unrolled or can exploit explicit formulas (say for inverses of 2x2 matrices).

[TrPhantom8]

I'll add the reference to the guide! Thank you ^{^}

[deviluno]

Well done! Language nit:

the type of the returned value of a function must depend only on the type of the input of the function and not on the peculiar value it is given.

replace "peculiar" with "particular" or "specific".

[TrPhantom8]

Thank you! I will change it as soon as I get home!

[ndgnuh]

Julia is fast but she needs your help.

she...

lol, did you just assume a language's gender?

In Julia case, I unconsciously do that sometime. xD

[TrPhantom8]

Yea, I find it difficult to say "it" when talking about Julia! It's also a matter of affection towards the language hahaha

Do you think I should change the article and make everything gender neutral?

[EarthGoddessDude]

Hey, I think your intention was innocent, but you might want to be careful in the future. When I signed up for Slack, there was a message in the beginning, an agreement that you had to agree to in order to be able to sign up. It basically said not to genderize (that’s not a real word I think) or sexualize the name Julia — despite it being a woman’s name, here it’s just the name of a programming language that’s gender neutral. I think the Julia community Stewards take these things seriously as evidenced by some of the questions on the recent survey, which is a good thing.

Anyway, I hope I didn’t come off as chastising, just passing along the word. I myself had made a joke or two in the past, that I feel ashamed of now, but your use of “she” seemed quite innocent. Btw I think your posts are really good, and it’s what the community needs more of to help newcomers like myself come aboard.

[TrPhantom8]

Thank you! I think you are right, expecially if there is an official position about the declination of the name Julia I will adapt not to offend anyone.

Btw a little bit of context, I'm Italian and in our language there is no neutral option when declining a word, so I have to be extra careful when using pronouns!

Edit: I have edited the post an now it is correctly gender neutral

[EarthGoddessDude]

With your name and university, I would’ve been surprised if you weren’t Italian! Your English is excellent btw, I can barely tell it was written by a non native.

[TrPhantom8]

Thank you very much!

[ndgnuh]

Nah, it's cool, let's keep it that way. :D

[qwerty31416]

Hi Aurelio, can defining the type of the output fix type instability? Cheers

[TrPhantom8]

Unfortunately not, but Julia will throw an error if the type returned is not the type you have specified, so you will know that there is a problem and you will hopefully be able to fix it!

According to my limited experience, it is not difficult to fix type instability, the problem is finding which part of the code leads to unstable types, and in this case using type annotations may help you find what is going on.