Claas Voelcker
@cvoelcker.bsky.social
For professional, see https://cvoelcker.de
If I seem very angry, check if I have been watered in the last 24 hours.
Now 🇺🇸 flavoured, previously available in 🇨🇦 and 🇩🇪
If I seem very angry, check if I have been watered in the last 24 hours.
Now 🇺🇸 flavoured, previously available in 🇨🇦 and 🇩🇪
Pinned
Claas Voelcker
@cvoelcker.bsky.social
· Nov 11
I'm Claas, a hopefully-soon-finished-PhD researcher at @uoft.bsky.social . I work on reinforcement learning, especially on deep model-based methods, and am dabbling in diffusion policies and large-scale imitation learning.
I'm way too political and loud in general, so please be warned.
I'm way too political and loud in general, so please be warned.
And most importantly, I'm at least 200% nicer than I appear in any given moment, so let me know if you really just want to geek out about random shit!
It is as if thousands of researchers suddenly cried out in terror and were suddenly silenced
November 11, 2025 at 9:03 PM
It is as if thousands of researchers suddenly cried out in terror and were suddenly silenced
LMAO, openreview down point 9pm UCT when ICLR is supposed to be releasing. Coincidence?
November 11, 2025 at 9:01 PM
LMAO, openreview down point 9pm UCT when ICLR is supposed to be releasing. Coincidence?
Damn, ICLR do be late this year
November 11, 2025 at 8:56 PM
Damn, ICLR do be late this year
Reposted by Claas Voelcker
AI could end scarcity, end humanity - or boost trend growth by 0.2 percentage points
November 7, 2025 at 1:24 PM
AI could end scarcity, end humanity - or boost trend growth by 0.2 percentage points
There is a reason an (almost) necessary step in getting a faculty position anywhere in the world is to move to the US for a bit. You suddenly become so much more attractive both inside and outside of the states. This is not good, and university hiring committees as well as governments are at fault.
It’s hard not to feel insulted by the Canadian federal budget’s implication that researchers currently working in Canada aren’t good enough, so they’ll spend a bunch of taxpayer money to bring in “top talent” from elsewhere.
November 6, 2025 at 12:07 AM
There is a reason an (almost) necessary step in getting a faculty position anywhere in the world is to move to the US for a bit. You suddenly become so much more attractive both inside and outside of the states. This is not good, and university hiring committees as well as governments are at fault.
Even though I grieve leaving Toronto, I have to begrudgingly admit that the University of Texas at Austin is pretty gorgeous 😁
November 4, 2025 at 9:49 PM
Even though I grieve leaving Toronto, I have to begrudgingly admit that the University of Texas at Austin is pretty gorgeous 😁
Reposted by Claas Voelcker
Training LLMs end to end is hard. But way more people should, and will, be doing it in the future.
The @hf.co Research team is excited to share their new e-book that covers the full pipeline:
· pre-training,
· post-training,
· infra.
200+ pages of what worked and what didn’t. ⤵️
The @hf.co Research team is excited to share their new e-book that covers the full pipeline:
· pre-training,
· post-training,
· infra.
200+ pages of what worked and what didn’t. ⤵️
November 2, 2025 at 3:17 PM
Training LLMs end to end is hard. But way more people should, and will, be doing it in the future.
The @hf.co Research team is excited to share their new e-book that covers the full pipeline:
· pre-training,
· post-training,
· infra.
200+ pages of what worked and what didn’t. ⤵️
The @hf.co Research team is excited to share their new e-book that covers the full pipeline:
· pre-training,
· post-training,
· infra.
200+ pages of what worked and what didn’t. ⤵️
Comparing furniture prices in the US to Canada shows the massive impact of recent policy. I am floored by how expensive IKEA furniture is here...
November 3, 2025 at 2:52 AM
Comparing furniture prices in the US to Canada shows the massive impact of recent policy. I am floored by how expensive IKEA furniture is here...
The only thing that makes twitter vaguely more attractive than bsky is that I miss @miniapeur.bsky.social here
October 27, 2025 at 4:19 PM
The only thing that makes twitter vaguely more attractive than bsky is that I miss @miniapeur.bsky.social here
I opened twitter (yes, I know, error in itself) and now I'm weirdly depressed again. I don't even get how people say "It has all of the AI news" when most of those AI news are delivered with a certain "You are worth less than a cockroach if you don't breathe $100m startup air"-ne-quoi.
October 27, 2025 at 2:46 PM
I opened twitter (yes, I know, error in itself) and now I'm weirdly depressed again. I don't even get how people say "It has all of the AI news" when most of those AI news are delivered with a certain "You are worth less than a cockroach if you don't breathe $100m startup air"-ne-quoi.
Reposted by Claas Voelcker
I think I posted about it before but never with a thread. We recently put a new preprint on arxiv.
📖 Replicable Reinforcement Learning with Linear Function Approximation
🔗 arxiv.org/abs/2509.08660
In this paper, we study formal replicability in RL with linear function approximation. The... (1/6)
📖 Replicable Reinforcement Learning with Linear Function Approximation
🔗 arxiv.org/abs/2509.08660
In this paper, we study formal replicability in RL with linear function approximation. The... (1/6)
Replicable Reinforcement Learning with Linear Function Approximation
Replication of experimental results has been a challenge faced by many scientific disciplines, including the field of machine learning. Recent work on the theory of machine learning has formalized rep...
arxiv.org
October 26, 2025 at 2:16 PM
I think I posted about it before but never with a thread. We recently put a new preprint on arxiv.
📖 Replicable Reinforcement Learning with Linear Function Approximation
🔗 arxiv.org/abs/2509.08660
In this paper, we study formal replicability in RL with linear function approximation. The... (1/6)
📖 Replicable Reinforcement Learning with Linear Function Approximation
🔗 arxiv.org/abs/2509.08660
In this paper, we study formal replicability in RL with linear function approximation. The... (1/6)
STOP PUTTING UNRELATED THEORY IN YOUR PAPERS! STOP DEMANDING UNRELATED THEORY IN PAPERS! (DO demand related theory in your reviews, if applicable. But for deep learning, mostly suggest more interesting experiments, not simply more experiments).
October 23, 2025 at 9:00 PM
STOP PUTTING UNRELATED THEORY IN YOUR PAPERS! STOP DEMANDING UNRELATED THEORY IN PAPERS! (DO demand related theory in your reviews, if applicable. But for deep learning, mostly suggest more interesting experiments, not simply more experiments).
I have decided that my "grumpy researcher soap-box" is going to be "Reward hacking is a wrong term, say 'reward mis-specification'". Because its not your algorithm's fault that its doing its job, its your fault for not telling it properly what the job was. Define your objectives well!
October 21, 2025 at 5:18 PM
I have decided that my "grumpy researcher soap-box" is going to be "Reward hacking is a wrong term, say 'reward mis-specification'". Because its not your algorithm's fault that its doing its job, its your fault for not telling it properly what the job was. Define your objectives well!
Sometimes I wonder why I do research. It's slow and boring, and I mostly just browse bsky or reddit. Then, sometimes, you get an IDEA and for a week or so the separation between you and the research disappears and the IDEA becomes your (second) true love (shoutout hubby).
October 21, 2025 at 4:36 PM
Sometimes I wonder why I do research. It's slow and boring, and I mostly just browse bsky or reddit. Then, sometimes, you get an IDEA and for a week or so the separation between you and the research disappears and the IDEA becomes your (second) true love (shoutout hubby).
You: Your post-per-day rate has gone up drastically...
Me: Yes, it's ICLR review time, why do you ask?
#procrastiskeeting
Me: Yes, it's ICLR review time, why do you ask?
#procrastiskeeting
October 20, 2025 at 5:01 PM
You: Your post-per-day rate has gone up drastically...
Me: Yes, it's ICLR review time, why do you ask?
#procrastiskeeting
Me: Yes, it's ICLR review time, why do you ask?
#procrastiskeeting
Also, coming up with unhinged strategies to self-cite in co-authored papers: just add a bunch of self-citations in white color at the end of the latex doc, even if they don't fit! Your co-authors won't notice new papers appearing in the bibliography anyways (who reads a bibliography???)
#timgilling
#timgilling
Remember folks, if your h-index isn't at least floor(n/2) after n papers, you aren't self citing enough! 🦝
October 20, 2025 at 3:33 PM
Also, coming up with unhinged strategies to self-cite in co-authored papers: just add a bunch of self-citations in white color at the end of the latex doc, even if they don't fit! Your co-authors won't notice new papers appearing in the bibliography anyways (who reads a bibliography???)
#timgilling
#timgilling
Remember folks, if your h-index isn't at least floor(n/2) after n papers, you aren't self citing enough! 🦝
October 20, 2025 at 3:29 PM
Remember folks, if your h-index isn't at least floor(n/2) after n papers, you aren't self citing enough! 🦝
How are some PhD students on 10 - 15 papers a year? With 5 first author papers? Just, genuinely, what is going on there? That means on average 2 months per paper and input on 5 - 10 more papers in the same time?
October 20, 2025 at 3:26 PM
How are some PhD students on 10 - 15 papers a year? With 5 first author papers? Just, genuinely, what is going on there? That means on average 2 months per paper and input on 5 - 10 more papers in the same time?
Reposted by Claas Voelcker
Microsoft hates computers AND everyone who uses them, whereas Apple only hates computers, and Linux only hates the people who use them. In this essay I will
October 16, 2025 at 6:19 PM
Microsoft hates computers AND everyone who uses them, whereas Apple only hates computers, and Linux only hates the people who use them. In this essay I will
Reposted by Claas Voelcker
Welcome to bluesky, make it better by using the For You feed: bsky.app/profile/spac...
October 16, 2025 at 1:08 AM
Welcome to bluesky, make it better by using the For You feed: bsky.app/profile/spac...
i literally had an algorithm idea come to me in a fever dream, but it works???
October 15, 2025 at 8:02 PM
i literally had an algorithm idea come to me in a fever dream, but it works???
value functions are a mirage
October 15, 2025 at 7:59 PM
value functions are a mirage
Reposted by Claas Voelcker
Apply to join one of the top AI research 🤖 institutes in the world in the wonderful city of Montréal!
I will be recruiting 1-2 students this year. Just mention my name in your application.
I will be recruiting 1-2 students this year. Just mention my name in your application.
Mila's annual supervision request process is now open to receive MSc and PhD applications for Fall 2026 admission! For more information, visit mila.quebec/en/prospecti...
October 15, 2025 at 3:41 PM
Apply to join one of the top AI research 🤖 institutes in the world in the wonderful city of Montréal!
I will be recruiting 1-2 students this year. Just mention my name in your application.
I will be recruiting 1-2 students this year. Just mention my name in your application.
Honestly, theory people would be so much more celebrated and cited if they didn't insist on removing _all_ intuition from their papers about why their methods work :D Sooooooooo much labour in reverse engineering the intuitions, which often turn out to be pretty simple.
October 14, 2025 at 3:37 PM
Honestly, theory people would be so much more celebrated and cited if they didn't insist on removing _all_ intuition from their papers about why their methods work :D Sooooooooo much labour in reverse engineering the intuitions, which often turn out to be pretty simple.