Bruno Mlodozeniec
@brunokm.bsky.social
710 followers 31 following 14 posts
PhD in Deep Learning at Cambridge. Previously Microsoft Research AI resident & researcher at Qualcomm. I want to find the key to generalisation.
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brunokm.bsky.social
For example: for even moderately sized datasets, the trained diffusion models' marginal probability distribution stays the same irrespective of which examples were removed from the training data, potentially making the influence functions task vacuous.
brunokm.bsky.social
We also point out several empirical challenges to the use of influence functions in diffusion models.
brunokm.bsky.social
In our paper, we empirically show that the choice of GGN and K-FAC approximation is crucial for the performance of influence functions, and that following our recommended design principles leads to the better performing approximations.
brunokm.bsky.social
Influence functions require the training loss Hessian matrix. Typically, a K-FAC approximation to a Generalised Gauss-Newton (GGN) matrix is used instead of the Hessian. However, it's not immediately obvious which GGN and K-FAC approximations to use in the diffusion
brunokm.bsky.social
Influence functions are already being used in deep learning, from classification and regression through to autoregressive LLMs. What's the challenge in adapting them to the diffusion setting?
brunokm.bsky.social
• Identifying and removing data responsible for undesirable behaviours (e.g. generating explicit content)
• Data valuation (how much did each training datapoint contribute towards generating the samples my users pay me for?)
brunokm.bsky.social
Answering how a model's behaviour changes upon removing training datapoints could help with:
• Quantifying impact of copyrighted data on a given sample (how much less likely is it that the model would generate this image if not for the works of a given artist?)
brunokm.bsky.social
Influence functions attempt to answer: how would the model's behaviour (e.g. probability of generating an image) change if the model was trained from scratch with some training datapoints removed.

They give an approximate answer, but without actually retraining the model.
brunokm.bsky.social
How do you identify training data responsible for an image generated by your diffusion model? How could you quantify how much copyrighted works influenced the image?

In our ICLR oral paper we propose how to approach such questions scalably with influence functions.
brunokm.bsky.social
It’s an awesome piece of work, done on a surprisingly small budget compared to the performance
brunokm.bsky.social
Rich Turner with other members of our group recently published a paper on Aardvark — end-to-end weather prediction with deep learning — in Nature, and it was just featured in The Guardian and Financial Times!

www.theguardian.com/technology/2...
AI-driven weather prediction breakthrough reported
Researchers say Aardvark Weather uses thousands of times less computing power and is much faster than current systems
www.theguardian.com
brunokm.bsky.social
Myself, James and and Shreyas will be at NeurIPS presenting this work. Come chat to us if you’re interested!
jamesallingham.bsky.social
I'll be at NeurIPS next week, presenting our work "A Generative Model of Symmetry Transformations." In it, we propose a symmetry-aware generative model that discovers which (approximate) symmetries are present in a dataset and can be leveraged to improve data efficiency.

🧵⬇️
brunokm.bsky.social
Diffusion models are so ubiquitous, but it's difficult to find an introduction that is concise, simple and comprehensive.

My supervisor Rich Turner (with me & some other students) has written an introduction to diffusion models that fills this gap:

arxiv.org/abs/2402.04384
Denoising Diffusion Probabilistic Models in Six Simple Steps
Denoising Diffusion Probabilistic Models (DDPMs) are a very popular class of deep generative model that have been successfully applied to a diverse range of problems including image and video generati...
arxiv.org