arXiv Machine Learning

Truncate or Not? A Scaling Study of Looped Transformers with Truncated Backpropagation

arXiv Machine Learning
Sep 17

How Model Growth, Recursion, and Boundary Operators Influence Scaling Exponents

The paper demonstrates that architectural changes—specifically looped transformers and boundary operators—can alter scaling exponents in pre‑training, yielding exponential performance gains for a given computational budget. Looping, or recursive depth, enables model growth that matches larger models (e.g., a 7.4B looped architecture matching GPT‑3 13B) with significantly less compute, while boundary operators provide additional, though smaller, efficiency improvements. In data‑constrained, multi‑epoch scenarios, increasing loops with scale serves as a useful regularizer, suggesting that deeper computational depth drives compute‑efficiency gains that grow with model size.

By Zixi Chen, Akshay Vegesna, Samip Dahal, Andrew Gordon Wilson
arXiv AI
Oct 2

Looping Beyond Twice: A Scalable Recipe for Looped Mixture-of-Experts

The paper introduces LOOM, a method for scaling looped mixture‑of‑experts (MoE) Transformers beyond the typical two‑loop limit. LOOM addresses two key obstacles: it stabilizes deep recurrence by bounding residual variance and re‑injecting the input embedding, and it prevents expert selection collapse by using per‑loop routers and a looping residual to maintain computational diversity. Experiments on 100 M–1.7 B parameter models show stable scaling to 9–12 loops, with significant perplexity reductions and zero‑shot accuracy gains under near‑iso‑FLOP conditions.

By Di He, Pengxiang Li, Da Chang, Qingyan Meng, Lu Yin, Shiwei Liu
arXiv AI
Oct 5

The Surprising Effectiveness of Shared Memory in Looped Transformers

The paper introduces a method for looped transformers that share a key‑value cache across recursions, reducing memory usage without sacrificing quality. Experiments show that the Looped Prediction Transformer (LPT) and its hybrid variant achieve lower perplexity on FineWeb‑Edu while using 76‑79% less context memory compared to standard transformers. Analysis reveals that shared memory develops distinct representations and serves as a gradient highway, enabling later recursions to focus on shared information.

By Giovanni Monea, Keshav Ramji, Yousef El-Kurdi, Luis A. Lastras, Yoav Artzi, Nathan Godey, Ram\'on Fernandez Astudillo
arXiv Machine Learning
Sep 30

Looped Transformers as Optimizers

arXiv:2609.37379v1 Announce Type: new Abstract: Looped Transformers provide a parameter-efficient approach to depth scaling by repeatedly applying shared Transformer blocks. Recent reasoning models h...

By Yulong Huang, Chen Jiang, Zhanpeng Zhou, Hongtao Zhang, Tianyu Li, Tianyu He, Xiangyu Zhang, Bojun Cheng