📚 Journal club on discrete diffusion models
🎥 Replays available on YouTube!
Contact: [email protected]
Hosted by @ssahoo_, @jdeschena, @zhihanyang_d-llms.comJoined August 2025
📢 June 15 (Mon): Uniform Diffusion Models Revisited: Leave-One-Out Denoiser and Absorbing State Reformulation
🤔 Discrete diffusion models are often trained through clean-data prediction, but the prediction can be used in different ways to define the reverse dynamics. In Masked
📢 June 15 (Mon): Uniform Diffusion Models Revisited: Leave-One-Out Denoiser and Absorbing State Reformulation
🤔 Discrete diffusion models are often trained through clean-data prediction, but the prediction can be used in different ways to define the reverse dynamics. In Masked Diffusion Models (MDM) these choices largely coincide, whereas in Uniform Diffusion Models (UDM) they do not.
💡 The authors show that the standard plug-in bridge parameterization for UDM is not optimized by the denoising posterior, but by a leave-one-out posterior that predicts each clean token without using its own noisy observation. This identifies a mismatch between the plug-in ELBO and the usual cross-entropy denoising objective.
🔧 The authors characterize the leave-one-out target and derive exact conversions between the denoiser, the leave-one-out posterior, and the score. These conversions allow them to disentangle parameterization and the training objective.
📈 Their results also lead to inference improvements without any additional training through an informed predictor-corrector sampler and improved temperature sampling based on the leave-one-out predictor.
🔧 The authors further introduce an absorbing-state reformulation of uniform diffusion that preserves the UDM joint law while decomposing it into masked-diffusion-like sampling operations, with simpler denoising posteriors, carry-over unmasking, and a natural remasking mechanism.
📈 On language modeling, leave-one-out parameterizations consistently improve UDM generation, while the absorbing construction matches or surpasses masked diffusion. These results suggest that the empirical gap between masked and uniform diffusion is driven less by the choice of marginals themselves than by parameterization and sampling design.
This Monday, Samson Gourevitch (@samsongvch, samsongourevitch.github.io), Yazid Janati (@yjelid, yazidjanati.github.io), and Dario Shariatian (@dario_sha, darioshar.github.io) will present their paper "Uniform Diffusion Models Revisited: Leave-One-Out Denoiser and Absorbing State Reformulation".
📢 June 15 (Mon): Uniform Diffusion Models Revisited: Leave-One-Out Denoiser and Absorbing State Reformulation
🤔 Discrete diffusion models are often trained through clean-data prediction, but the prediction can be used in different ways to define the reverse dynamics. In Masked
Curious what’s under the hood of DiffusionGemma?
Begin with these two tutorials covering its foundational building blocks:
1. Uniform-state Diffusion: youtu.be/FCO-nnqHOqQ?si…
2. Block diffusion: iclr.cc/virtual/2025/o…
Want to understand what powers DiffusionGemma?
Start with these two tutorials on its core building blocks:
1. Uniform-state Diffusion: youtu.be/FCO-nnqHOqQ?si…
2. Block diffusion: iclr.cc/virtual/2025/o…
Meet DiffusionGemma!
An experimental open model that explores a fast approach to text generation, released under an Apache 2.0 license.
Moving beyond sequential, token-by-token processes to generate entire blocks of text simultaneously. Here’s what’s new with DiffusionGemma: 👇
📢 June 8 (Mon): Entropy-Gated Continuous Bitstream Diffusion for Language
🤔Diffusion language models (DLMs) promise parallel, order-agnostic generation, but on standard benchmarks they have historically lagged behind autoregressive models in sample quality and diversity.
🔥 New paper: BlockGen: Flexible Blockwise Sequence Modeling with Hybrid Samplers
Are uniform-state diffusion models (USDMs) always stronger than masked (MDMs) ones? Recent work suggests so. However, a few questions remain open 🤔
w/ @caglarml
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Most language models generate text the way a typewriter works. They go left to right, one token at a time.
Diffusion language models generate entire sequences by simultaneously refining noise into meaning.
📢 June 8 (Mon): Entropy-Gated Continuous Bitstream Diffusion for Language
🤔Diffusion language models (DLMs) promise parallel, order-agnostic generation, but on standard benchmarks they have historically lagged behind autoregressive models in sample quality and diversity.
📢 June 8 (Mon): Entropy-Gated Continuous Bitstream Diffusion for Language
🤔Diffusion language models (DLMs) promise parallel, order-agnostic generation, but on standard benchmarks they have historically lagged behind autoregressive models in sample quality and diversity.
💡Recent continuous flow and diffusion approaches over token embeddings have narrowed this gap, suggesting continuous state spaces are highly effective for language. In this work, the authors further close the autoregressive gap by modeling text as a continuous diffusion process over fixed-width binary bitstreams.
🔧Their approach represents semantic tokens as analog bit sequences and utilizes a matched-filter residual parameterization to isolate contextual learning from analytic independent-bit posteriors. Crucially, they adopt a stochastic sampler that applies Langevin-type corrections gated by the entropy-rate profile, automatically concentrating stochasticity in high-information regions while remaining nearly deterministic elsewhere.
📈On the One Billion Word Benchmark (LM1B), their 130M-parameter bitstream model reaches a generative perplexity (Gen. PPL) of 59.76 at matched real-data entropy (4.31) using 256 neural function evaluations (NFEs), decisively outperforming prior DLM baselines and reaching the autoregressive reference. On OpenWebText (OWT), the authors' stochastic sampler establishes a new continuous-DLM Pareto frontier, achieving Gen. PPL = 27.06 at an entropy of 5.26 using 4× fewer steps than previous 1024-NFE baselines.
🌍As an additional architectural benefit, bitstream diffusion removes the O(V) vocabulary scaling bottleneck shared by standard DLMs. By predicting O(log V) bitwise logits via semantic bit-patching, the model yields a reduced memory footprint and higher throughput, demonstrating a scalable paradigm for language generation as vocabulary sizes grow.
This Monday, Georgios Batzolis (@GBatz97, gbatzolis.github.io) will present his recent work “Towards Closing the Autoregressive Gap in Language Modeling via Entropy-Gated Continuous Bitstream Diffusion”.
Discrete Diffusion Tutorial @CVPR tomorrow (Wednesday).
Tutorial name: The Principles of Diffusion Models
Real-Time Continuous & Discrete Diffusion
Location: Colorado Convention Center, Four Seasons 4 - Rooms 301 / 302
Dm me if you'd like to attend it remotely on Zoom.
w/ @JCJesseLai@yukimitsu
📢 June 1 (Mon): ELF: Embedded Language Flows
🤔Unlike their image-domain counterparts, today’s leading diffusion language models (DLMs) primarily operate over discrete tokens.
💡The authors show that continuous DLMs can be made effective with minimal adaptation to the discrete
📢 June 1 (Mon): ELF: Embedded Language Flows
🤔Unlike their image-domain counterparts, today’s leading diffusion language models (DLMs) primarily operate over discrete tokens.
💡The authors show that continuous DLMs can be made effective with minimal adaptation to the discrete
174 Followers 289 FollowingPhD Student @irisa_lab. Graph Representation Learning and Geometric Deep Learning. You can find me tuning my model’s weights or weights at the gym.