Eric Zhang

Wrote a bit this morning on the internals of ML compilers, and how I'm going about porting JAX to pure JS ekzhang.substack.com/p/how-the-jaxj…

drops an absolute banger, does research to figure out the hardest IMO math problems with sheer number crunching and reasoning muscle over hours I guess dropping in on our olympiad training programs to flex on the high schoolers years ago wasn’t enough, had to automate it away:D

…and, 500 lines of code later, jax-js now supports advanced indexing! it turns out this is roughly a "gather" operation, so I named it that internally in my IR, following XLA. however, backprop through this requires a "scatter" op which is much harder, so I'm skipping that 😅

tens of millions of hours have been spent on software that… records a mapping of keys and values

trying to figure out how to use the Google Cloud console is probably harder than defusing a bomb

saw ray chen and nyo playing mendelssohn! omg 🥹

I have fixed it 🤩 yay now that MNIST is finally debugged for sure, I can do some more features and move onto trying some harder problems with this library

hmm something is still subtly wrong with my kernels jax-js is generating, specifically in a loop-unroll optimization. :( it's not evident at first, but in this little mnist inference demo, it's def not working when the training used a batch size divisible by 4 and was unrolled

the story was, in June, I was so excited about a "Marimo cloud" that I went to their office & we hacked together the first prototype of a Modal Sandbox backend for Marimo in a couple hours. just a month later, guess they have a whole new cloud-based product, still on Modal :D

so I was up coding last night and then I checked the time and realized I turned 24 slight panic for a few seconds (like when you realized you missed a deadline or something) and then I remembered… there was no deadline after all

before I worked in infra, I used to read cloudflare’s incident writeups and think they were cool and mature now, since I notice every cloudflare outage, multiple times per month, my attitude is like “ok I get you can do good writeups, but please—just stop having outages”

this is still very scuffed, but I got MNIST to train in jax-js finally! spent like a week debugging, it's quite humbling to struggle so much on MNIST, found some tricky bugs in my autograd implementation & WebGPU kernel compiler anyway this, I guess, is another milestone :)

i feel a bit of emotional whiplash from past couple weeks, but it's been alright good things that happened recently: - ran into grade school classmate - learned tensor calculus - card game club - company acq'd jamsocket(yay!) - back into jax-js - used my notebooks product a lot

some notes from nysrg today, running a couple profiling tools on uv and touring it a bit to get situated from the performance angle github.com/ekzhang/nysrg-…

the weather has no business being like this. it’s kind of a holiday in itself, strolling through a city under the sun

i am currently in indexing hell trying to understand all the edge cases of numpy that I never thought about apparently if you combine slices and broadcasted integer array indexing, it orders the axes, _unless_ the arrays are non-contiguous, in which case they hoist to the front

This month at NYSRG, we'll do some systems studies through the lens of performance by looking at open-source software and profiling them on some workloads. the systems: uv, vLLM, an image renderer in Rust, and various language/compiler tools in Go the tools: flame graphs, ebpf,…

somewhere, under all of the politics and business of this AI hiring news, previously-unheard names; there's an optimistic message that these researchers' work is finally recognized — just as all great work may be

a milestone for jax-js — it's _working_ enough to generate and dispatch a few hundred GPU compute kernels for a Mandelbrot set render, all from your browser in milliseconds :D (this does a separate allocation + kernel dispatch on each iteration, so it's a nontrivial benchmark)

btw modal is hiring for a product engineering manager. we have a very cool product engineering team that works with svelte to turn infrastructure into tech that developers love, since it helps them do more :) apply here jobs.ashbyhq.com/modal/51d11ce0…

yesterday i voted and i think the most surreal part of it was that my family member who got all of us to go to the polls and vote for him is literally a wall st banker, like damn i’ve never been very politically involved but it did feel nice to imagine what could be