kmaitreys
Born on December 04, 2025•88 Karma
Last thing I saw Karpathy talk about was this, which I find hard to believe that it came from a smart person.
And, my objection was that he clearly had no understanding of the supply-chain risk he was worsening by advocating widespread use of Obsidian for agentic engineering tasks.
Since his announcement, Obsidian has taken proactive steps to mitigate the risks, or at least study threat model. Hopefully, they will implement proper RBAC or something before someone else with his visibility announces an even more irresponsible half-baked idea.
To those who regularly write Julia code, what is your workflow? The whole thing with Revise.jl did not suit me honestly. I have enjoyed programming in Rust orders of magnitude more because there's no run time and you can do AOT. My intention is not write scripts, but high performance numerical/scientific code, and with Julia's JIT-based design, rapid iteration (to me at least) feels slower than Rust (!).
In my experience you really gotta work with the tools the language gives you. Julia gives you Revise, so it’s a bit of a handicap not using it. Maybe analogous to writing Rust without an LSP.
I get that leaning on the LSP can become a habit, and also that the Julia LSP is quite poor, but I find it wild that rapid iteration for you is faster in Rust. I write Rust as well and can’t imagine how that would be the case.
rust-analyzer is a great LSP and paired with clippy it can teach you the language itself. Also, writing numerical code is extremely easy in Rust. I can write code and just run cargo run to see the output. Julia, on the other hand, forced a REPL-based workflow which never has made sense to me. REPL-based workflow makes sense when you just want to do some script stuff. But when writing a code which will run for a long duration on a HPC? I don't get it. Part of the problem is I'm not "holding it correctly", but again, out of the box experience isn't good. You define a struct and later add or remove a field from it. Often you'll get an error because Revise.jl didn't recompile things. It was a sub-par experience and I was hoping to people would share their dev workflow in more detail
Recent versions of Revise let you redefine structs in the REPL.
You are not forced to use the REPL, ever. It’s a fantastic convenience, however.
My dev workflow is to write my code in Neovim, sometimes with a REPL attached to the editor to try out code snippets. I don’t need or use LSPs. I do enjoy the Aerial plugin, which pops up an outline of my code for easy navigation.
Nowadays I often use Claude Code, working with a Julia REPL in a tmux or zellij session via send-keys. I'll have it prototype and try to optimize an algorithm there, then create a notebook to "present its results", then I'll take the bits I like and add them to the production codebase.
REPL-based workflow doesn't make sense to me other than scripting work.
For long-running jobs, I basically follow the same process as in any other language: make the functions I want to run, test them locally on a small dataset that runs relatively quickly, then launch them on the remote machines with the full data.
Revise.jl has struct redefinition now, but before that I would just use NamedTuples while iterating, then make a struct when I was ready to move something to production.
`using` is for importing modules, `include` is for specific files. At work, we currently have a monorepo, with one top-level OurProject.jl file that uses `using` to import external packages, and `include` for all the internal files.
The main strategy is to have a way of parameterize the program to bring the runtime down to seconds-minutes on a laptop. E.G. for PDEs, you may be running the HPC version on a giant mesh, but you can run the same algorithm on your local computer on a much coarser mesh.
> How do you quickly modify struct definitations
Thankfully on 1.12 this has been solved. You can redefine structs while keeping the REPL up.
> how do you define imports (using vs include syntax is so confusing!)
Yeah julia messed this up. The basic rule is that include and using are basically the same.
I hope julia developper tools will one day match the best of what other programming languages have to offer.
If you want a better Julia LSP, you might just be able to get Claude or Codex to build one for you. I've been impressed with the TLA+ bindings it generated.
Good LSPs do the autocompletion, sub par ones don't.
Is it really such a good idea to have every single automated aid turned on when picking up a new language?
How will you learn if you cannot get feedback on what you did wrong?
I mean, until you learn multiplication, maybe don't use the calculator.
Once you learn it then you get a small speed increase, but if you are new to something, LSP autocompletion is going to slow down your learning.
Speaking authoritatively from my position as an incompetent C++ / Rust dev.
Because passing pointers isn't as ergonomic in Rust, I do things in arena-based way (for example setting up quadtrees or octrees). Is that part of the issue when it comes to memory bandwidth?
For now my plan is to write fairly similar style code as one may write in C++/Fortran through MPI bindings in Rust.
if you take that one step further and only use those objects on a single core, now your default model is lock-free non-shared objects. at large scale that becomes kind of mandatory. some large shared memory machines even forgo cache consistency because you really can't do it effectively at large scale anyways.
but all of this is highly platform dependent, and I wouldn't get too wrapped up around it to begin with. I would encourage you though to worry first about expressing your domain semantics, with the understanding that some refactoring for performance will likely be necessary.
if you have the patience and personally and within the project, it can be a lot of fun to really get in there and think about the necessary dependencies and how they can be expressed on the hardware. there's a lot of cool tricks, for example trading off redundant computation to reduce the frequency of communication.
There's a lot of useful advice here that'll surely come in handy to me later. For now, yeah I'm just going to try to make things work. So far I have mostly written intra-node code for which rayon has been adequate. I haven't gotten around to test the ergonomics of rs-mpi. But it feels quite an exciting prospect for sure.
Also what benchmark? How will you you design it?
Children learning in schools should not become product managers. If they are, what exactly is the "product" that they are "managing"? Reducing everything to and looking everything from a corporate viewpoint is bizarre.
Regarding education I think AI is a huge revolution waiting to happen. Usual courses have become boring? Have future super powerful AI generate per student highly personalized programs, create bespoke video games where succeeding can only happen once the student has validated all the notions you wanted them to validate etc.
None of this is equivalent to the topic of discussion. The point is that even in a world of division of labour and shared expertise, there is no atrophy in general populace because someone is trying to become expert in something. The whole point is that the brain is being put in use to do something. If not in X, then in Y. If none of the alphabets are available, where do you put your brain in use to?
>I would not assume someone who won the lottery is going to have their life become uninteresting or see some cognitive decline. It could probably happen, but you can also see a path where the person just chooses to do the activities they always wanted to do, where they keep learning and exploring without the burden of usual life constraints. People already play chess when machines have beaten us for decades, just because they enjoy it.
Again, please play attention to the main idea of the article linked. Most of cognitive development happens in the early formative years. Yes, learning itself never stops, but the primary period of it during perhaps the first 25 years of someone's life. You NEED to make mistakes and learn from them during this period. If you are offloading work that your brain was supposed to do here, it's extremely worrying.
>Regarding education I think AI is a huge revolution waiting to happen. Usual courses have become boring? Have future super powerful AI generate per student highly personalized programs, create bespoke video games where succeeding can only happen once the student has validated all the notions you wanted them to validate etc.
I think there is some truth to it, but you need to regulate how much AI can assist a student. It can be a patient teacher but it shouldn't replace their cognitive abilities. That is the whole point.
I get that people love saying LLMs are just compilers from human language to $OUTPUT_FORMAT but... they simply are not except in a stretchy metaphorical sense.
That's only true if you reduce the definition of "compiler" to a narrow `f = In -> Out`. But that is _not_ a compiler. We have a word for that: function. And in LLM's case an impure one.
Then what is the point? Why be averse so to use your own brain so much? Why are tech bros like this?