After 600 experiments, here's what I discovered about JEPA world models
199 points - yesterday at 5:55 PM
SourceComments
> (3) That's where I decided to build a harder test, where each task takes its start from one demonstration and its goal from another
> (4) I also built an interactive demo where I could place the block anywhere and pick any goal. [but] The goals in the harder test are frames from expert demonstrations
Why lean so hard on the demonstration examples? Surely the actual task here is to move between any two arbitrary poses.
So if the demonstration set is statistically strange in any way, you keep banging into that. And even if you get great results, you still haven’t shown that it generalizes to the generic system. And the one thing you know 100% about a physical robot system is that you will never encounter exactly the same situation twice.
Is there actually a reason to pick eval examples from the demonstrations instead of independent samples from the underlying task?
I’m pretty sure that the T-shoving problem doesn’t have goal reachability issues. And if it did, test 4 could run into them since the start pose is arbitrary.
In the planning stage, by factoring out the optimization step from the rollout step, you can free the model to focus on learning the dynamics in latent space. (The other case, where the rollout+optimization happen in the learning loop, just becomes model-free RL.)
My background straddles classical & data-driven controls. This was the first similarity that popped out to me when I first started learning about world models.
Is JEPA just MPC but where the "M" is a latent-space model?
But maybe worth reframing away from “discovering” - hierarchical planning, sub-goals, action chunking etc. are well understood - this is more of a… transcript of your personal learning journey?
Which is still cool to see. But I read through expecting there to be some kind of novel results. We probably need to categorize these kinds of posts a bit better.
Awesome read!
If you’re going to use AI to generate text, keep it short and concise and meaty. I don’t hate reading AI, but I can’t read large walls of text for presumably some useful nugget of information in it.
https://www.pangram.com/history/2dd2b019-221a-4bee-bb6a-6b7e...
Anyway:
> The physics of pushing a block doesn't change if you shift, rotate or mirror the whole table. So when the graph has no states near a goal, it can take demonstration segments from elsewhere, transform them to fit the gap, and plan through those. With these transformed segments, success came back to 85%
This is an interesting technique to recover incomplete states or lost memories after demonstration. I'm guessing that the original LeWM does not have technique of transformative memories if I am correct?