Louis Béthune retweeted
Say hi to PUMBA! 🐗
Masked diffusion language models are trained one way and sampled another.
Our new paper studies how to make MDM training more aware of the trajectories followed at inference, and how this can lead to more efficient text generation.
Paper link below 🧵
Louis Béthune retweeted
We were all wondering whether Categorical Flow Maps (CFMs) could scale... 🤔
I couldn't help trying it out...
So we scaled CFMs to 1.7B parameters over 2.1T tokens 🚀🔥
Short summary 🧵⬇️
Louis Béthune retweeted
Autoregressive models dominate, but what if we treat multimodal generation as discrete order agnostic iterative refinement? Excited to share our systematic study on the design space of Tri-Modal Masked Diffusion Models (MDMs). We pre-trained the first Tri-Modal MDM from scratch on (text,), (image, text), and (audio, text). The same model can do ASR, TTS, T2I, captioning and native text generation.
What I'm the most proud of in this work is the scientific rigor. Over 3,500 training runs. Principled hyperparameter transfer. Honest results. Carefully controlled ablations across multiple different axis of entanglement.
A thread on our empirical findings (arXiV: arxiv.org/abs/2602.21472)
Louis Béthune retweeted
In our new work—Complete(d)P—we tackle 3 questions about hyperparameter (HP) scaling:
• How to transfer across model size, tokens&batch-size?→Complete(d)P
• Do per-module HPs matter?✔️2x speed-ups possible
• Do they transfer to larger scale?✔️ With the right parameterisation

ALT Abstract of a paper titled “Completed Hyperparameter Transfer across Modules, Width, Depth, Batch & Duration”. The paper describes a principled method for scaling up training by using a hyperparameter-transfer enabling parameterisation. The paper is relevant to people working on µP, scaling, reparameterisation rules, optimisation and pre-training.
Louis Béthune retweeted
We propose new scaling laws that predict the optimal data mixture, for pretraining LLMs, native multimodal models and large vision encoders !
Only running small-scale experiments is needed, and we can then extrapolate to large-scale ones. These laws allow 1/n 🧵
Louis Béthune retweeted
and Scaling Laws for Forgetting and Fine-Tuning (E-2708)
with @LouisBAlgue, David Grangier, Eleonora Gualdoni, Marco Cuturi, and @PierreAblin
🔗 icml.cc/virtual/2025/poster/…
Louis Béthune retweeted
This paper maps hardware-cost sweet spots for training efficient small-scale language models.
Data shows A100-40GB beats H100 for training cost-effective small language models
🎯 Original Problem:
Training small-scale LLMs (under 2B parameters) faces unclear computational bottlenecks. No systematic study exists on optimal hardware configurations and training dynamics for these models.
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🔧 Solution in this Paper:
• Analyzed training behavior up to 2B parameter models across:
- GPU types (A100-40GB, A100-80GB, H100-80GB)
- Batch sizes (4 to 64 per device)
- Communication protocols (DDP vs FSDP)
- Attention mechanisms (Vanilla vs FlashAttention)
- GPU counts (1 to 64)
• Used Token/Dollar and Token/Second as key metrics for cost efficiency
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💡 Key Insights:
• FlashAttention gives higher efficiency gains in smaller models
• A100-40GB is cost-optimal for smaller models
• H100 GPUs are not cost-efficient for training small LLMs
• DDP works better for smaller models due to less communication overhead
• FSDP outperforms DDP for 2B parameter models with large batch sizes
• Cost efficiency saturates before maximum GPU memory utilization
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📊 Results:
• FlashAttention enables training 1B-2B models with 512 batch size
• A100-80GB performs best for 1B-2B models with 32+ GPUs
• FSDP with gradient/optimizer state sharding beats full sharding
• DDP shows 20-30% better Token/Dollar for sub-1B models
Louis Béthune retweeted
Apple releases AIMv2
Multimodal Autoregressive Pre-training of Large Vision Encoders
Louis Béthune retweeted
🍏 Apple ML research in Paris has multiple open internship positions!🍎
We are looking for Ph.D. students interested in generative modeling, optimization, large-scale learning or uncertainty quantification, with applications to challenging scientific problems.
Details below 👇
Louis Béthune retweeted
👋👨🍳🍵 After a year of cooking up a secret project, I'm thrilled to officially reveal:
The 𝐋𝐄𝐍𝐒 𝐏𝐫𝐨𝐣𝐞𝐜𝐭.
By combining modern tools of Explainable AI, how much can we explain a ResNet50?
🧶
Louis Béthune retweeted
📢 *PhD opening* at
@inria_grenoble
! Edouard Pauwels, @vaiter and myself are looking for a student to work with us on learning theory for bilevel optimization, in particular, the implicit bias in bilevel optimization.
If interested, please reach out!
Louis Béthune retweeted
If you're interested in a student researcher position at Google DeepMind in 2024, please apply here google.com/about/careers/app… before December 15. My team will be looking for a student working on LLM finetuning on site in Paris.
Interested in results at the intersection between explainability🔍 and optimal transport 🚚? Come check out "On the explainable properties of 1-Lipschitz Neural Networks: An Optimal Transport Perspective" on Tuesday at 5:15pm, panel #1508.
Furthermore, the saliency maps are less noisy than the ones of conventional models, and importantly, more aligned with humans!
Mathieu Serrurier, Franck Mamalet, @Napoolar, @ThibautBoissin, and myself will be there to present it in panel #1508 on Tuesday afternoon. Come see us to chat! 👋
LLMs need a self-modifying code. Scaling-up the context won't be enough. Continual learning + machine unlearning are necessary ingredients to true read/write operations.
Louis Béthune retweeted
👋 Explain big vision model with 𝐂𝐑𝐀𝐅𝐓 🪄🐰
A method that 𝙖𝙪𝙩𝙤𝙢𝙖𝙩𝙞𝙘𝙖𝙡𝙡𝙮 extracts the most important concepts for your favorite pre-trained vision model.
e.g., we automatically discover the most important concepts on a ResNet50 for rabbits: eyes, ears, fur.
🧶
Louis Béthune retweeted
New work on Kernel regression on distributions arxiv.org/abs/2308.14335 where we prove that Rate of convergence is faster ! Applications to forecast distributional variability of 2016 US presidential election. @ANITI_Toulouse @LouisBAlgue @FBachoc





















