arXiv Machine Learning

A Mechanistic Study of Algorithmic Generalization in Diffusion Models on Modular Arithmetic

The paper investigates how diffusion models learn and generalize algorithmically, focusing on a modular addition task with images. In a single‑image setting, the model encodes operands as periodic representations and combines them via self‑attention and feed‑forward layers that mirror trigonometric addition identities. In a diverse‑image setting, the sampling process separates into an arithmetic computation phase and a visual refinement phase, with the transition marked by an internal frequency‑entropy signal.

arXiv AI
Oct 9

Probability-Signature Dynamics: Unpacking Modular Addition Learning Within Two-Layer Networks

The paper investigates why neural networks trained on modular addition tasks develop Fourier-structured representations that enable exact generalization. Using probability signatures, the authors show that leading gradient interactions are cyclic shift operators, which are diagonalized by the discrete Fourier transform, leading to decoupled Fourier-mode dynamics that explain Fourier sparsity, frequency matching, and phase alignment. The framework also clarifies how label noise can accelerate early loss decrease by increasing conditional label collisions, and it is demonstrated to predict frequency behavior in other operators such as XOR.

By Yunji Wang, Junjie Yao, Linyu Liu, Pinyan Lu, Zhi-Qin John Xu
arXiv Computer Vision
5d ago

Nemotron-Labs-Diffusion-Uni: Elastic Self-Refining Unified Diffusion LLM with Cross-Paradigm On-Policy Distillation

Nemotron‑Labs‑Diffusion‑Uni (NLD‑Uni) is a unified discrete diffusion large language model designed for visual understanding and generation. It introduces a cross‑paradigm on‑policy distillation framework that transfers capabilities from autoregressive VLMs and continuous flow models into a single DLLM, and a progressive self‑refining diffusion process that corrupts tokens gradually during training. Experiments show NLD‑Uni outperforms other unified DLLMs on tasks such as visual question answering, multi‑modal reasoning, object grounding, text‑to‑image generation, and image editing.

By Shufan Li, Hanrong Ye, Greg Heinrich, Yonggan Fu, Haotian Zhang, Sifei Liu, Aditya Grover, Pavlo Molchanov
arXiv AI
Oct 12

Neural networks are more modular than single neurons suggest

The paper argues that neural networks can exhibit modular organization even when individual neurons are not specialized. It introduces a nested hierarchy of modularity—unit-level, orthogonal, and linear—and shows that many vision, language, and RNN models lack unit-level modularity but still display clear functional modularity at the subspace level. The authors demonstrate that these subspaces can be causally validated through ablation and align with brain data, revealing distinct content/style or syntax/semantics separations.

By Shreya Saha, Benjamin Bergen, Meenakshi Khosla
Hugging Face Trending Papers
4d ago

Mode Dynamics: A Framework for Neural Network Learning

Mode Dynamics is a framework that links coordinated parameter motion during neural network training to changes in model outputs. By decomposing recorded parameter trajectories into collective modes and mapping each mode to its state‑dependent output effect, the framework uses decomposition, reconstruction, and concentration mechanisms to analyze how behavior emerges from parameter updates. Experiments on CIFAR‑100 autoencoding and a Pythia‑70M pretraining trajectory show that a small set of leading modes can reconstruct behavior, that induced effects depend on the training path, and that modal complexity varies with task and data.