Assistant Professor @mldcmu. Formerly: Postdoc @MITEECS, PhD @Berkeley_EECS, Math Undergrad @Princeton. New to Twitter. https://xitter.cf/t.co/67bMOAyqK6

Joined May 2024
Personal Update: I'll be splitting my responsibilities between CMU and Amazon FAR over the next year. I'm convinced we need a unified understanding of how the axes of scale, data, optimization and control interact for robot learning, and am excited for my lab + FAR to push towards uniting the "science of robot learning" with the "science of deep learning" at scale. Please reach out if you are looking for a full-time position building powerful multimodal AI models for deployment on hardware, and if you are intern looking to tinker and do good science on architectures, optimizers, data, tokenization, VLAs, WAMs and more!
16
4
1
513
34,934
Max Simchowitz retweeted
Hi all, I have a new result I'm excited to share. It turns out that *all existing implementations* of softmax and cross-entropy (that's JAX, PyTorch, textbooks, etc) have a subtle bug --- two bugs, actually. A simple rewrite fixes both, and eliminates "slingshots" when grokking:
133
772
142
6,342
749,077
This is one of my favorite projects I’ve been a part of this year. It’s ostensibly about robotics, but I feel that I learned something very fundamental about how AI models should represent all modalities that (superficially!) seem like they are best suited to being represented in continuous-valued (e.g. float) vectors. TL;DR discrete parametrizations are awesome, learn geometry from data, but aren’t constrained by it, and can perform better as a result. Exactly what the bitter lesson tells us we should look for.
Common belief: Robot policies need continuous action heads; discrete actions are 𝐥𝐞𝐬𝐬 𝐧𝐚𝐭𝐢𝐯𝐞 𝐚𝐧𝐝 𝐥𝐞𝐬𝐬 𝐩𝐫𝐞𝐜𝐢𝐬𝐞. ❗We find policies w/ the simplest discrete representations 𝐦𝐚𝐭𝐜𝐡 𝐨𝐫 𝐛𝐞𝐚𝐭 continuous ones—in sim & real, in single-step & diffusion/flow settings. Here's why 🧵
5
9
122
5,916
Ok, but aren’t you throwing away geometry with binned representations? No How does the policy know that nearby bins are “similar”?  Discrete policies learn geometry in their embeddings, rather than having them imposed from the continuous-vector representation of actions. This is peak bitter lesson.
1
1
205
Taken together, these results suggest (but do not yet prove!) a broader principle in AI: that discrete representations are really really really powerful, and enable greater policy expressivity. Stay turned for some more ambitious work coming out that will exploit these insights in VLA design and RL ;)
4
187
There seems to be fear reasoning models will trivialize research on robot learning architectures, algorithms, etc... I disagree. Innovation comes from constraints, and robotics imposes a ton of then. Our new paper, led by @DashoraNitish , suggests a really promising new direction for meeting the constraints of real robot deployment whilst capturing the "intelligence" of agentic reasoning models. Check it out!
There’s lots of buzz around agentic harnesses for robots, particularly for long horizon tasks that require complex reasoning and memory. But what will it really take to turn a reasoning agent into a reactive, reliable and low-latency robot policy? In our new paper, workspace models, we design a new memory architecture that acts as a latent harness for stronger reasoning models. Here’s why we think this might be the way forward: (1/9)
1
6
110
7,741
everyone talks about AI model alignment, but what about AI oligopoly alignment? Suppose a super powerful A̵I̵ ̵m̵o̵d̵e̵l̵ AI company thought it was acting in the public interest but was actually undermining it. How would we stop i̵t̵ them?
8
2
54
5,744
thoughts on robot/generative RL: the best regularization is more expressive updates, not less. What we've learned from the LLM community is that data and model scale lead to the most informative and stable gradients, and we should do the same in robotics.
6
2
108
8,847
A mathematical breakthrough used to effectively be defined as solving a problem that many smart people failed at for N years. Now a subset of those problems fall to LLMs with effectively zero human input and each gets announced as a breakthrough. Fair enough, by the old standard it is one. But the difficulty by which a breakthrough was defined, was measured against human effort. If a magic wand now solves them, how do we redefine difficulty in terms of the magic wand? A hard problem is one that resists the wand. Which leaves us with the actual question: What is now considered a breakthrough?
38
21
4
284
48,728
GPT can't write rebuttals like me bc no one writes rebuttals like a child of divorce
10
4
1
251
16,939
No one: Today's NeurIPS reviewers if it was 2015: "ResNet is incremental"
3
14
2
299
27,319
how well do frontier models make mathematical conjectures?
5
1
28
5,380
Robotics people, follow @aran_nayebi . He's been asking some really fundamental questions about what morphologies we need for robotics, and comes from a really unique bio/neuro perspective. Check this work out!
It's clear that to unlock the next big advances in robotics, we need at-scale tactile sensing. For the past year, in collab w/ @gs_ai_, we've been working on perhaps the most wide-ranging, realistic tactile simulator to ask: *What should the future of robot hands look like?*
4
6
155
31,746
Max Simchowitz retweeted
Diffusion / flow-based robot policies unlock two axes of test-time scaling: sequential (denoising steps) and parallel (samples). Both improve performance but cost latency on a robot, and knowing which to scale a priori is often unclear. ELASTIC learns it via RL!
4
20
3
96
25,356