What does JAX stand for?

[surak]

The acronym is not clear, and not mentioned anywhere. I suspect that A is from autograd, and X is from XLA, but the J?

[grahamgower]

Jit?

[surak]

I thought so, but JIT is already covered by the "X" from "XLA"

[hawkinsp]

@mattjj @froystig

Originally, it stood for "Just After eXecution", which refers to how JAX used to do tracing of functions. But JAX doesn't do it that way any more!

A more recent reinterpretation of JAX as an acronym is "JAX is Autograd and XLA". Even that's a bit inaccurate: JAX isn't the autograd project itself, instead its spiritual successor. JAX can also use both XLA and other compilers, so even the XLA part is a bit misleading.

So I think we don't really use JAX as an acronym anymore. JAX is JAX.

[mattjj]

I agree! Though actually I think "JAX is Autograd and XLA" is not so recent. In fact, JAX used to be built directly on top of https://github.com/hips/autograd, when it was just a baby project in 2017, though that hasn't been the case for a long time. Also, even though it's not literally accurate, that acronym is enshrined in the first line of the README:

I think Peter's right that there is no official acronym. Except we can retcon whatever acronym seems useful or humorous in the moment!

[jakevdp]

It stands for "JAX is an Acronym? ❌ "

[niklasschmitz]

I was pretty sure it was "Jacs" for Jacobians and xla!

[kasra-keshavarz]

"JAX Ain't XLA" Random post from the internet, didn't mean to be spam

[jpienaar]

Funnily enough I see folks have now started expanding it to Just Another XLA.

[NathanWycoff]

If there's no official acronym, can I humbly submit "Just Another XLA"?

This is in the spirit of "JAGS" - Just Another Gibbs Sampler, which is really anything but.

[mattjj]

Ah yes that was one we had too! "Just Another XLA-frontend".