arXiv Machine Learning

UpLoop: Training Looped Transformers via Upcycling at No Extra Pretraining Compute

UpLoop introduces a pretraining schedule that trains looped Transformers by upcycling early training computations, allowing the model to increase execution depth without adding extra parameters or training FLOPs. The method starts with a shallow Transformer, progressively copies learned layers to deepen the network, and reuses saved computation to support repeated execution of a shared middle block. Experiments across various model sizes demonstrate that UpLoop improves language modeling and downstream task performance, raising the average score across 22 tasks from 22.99 to 27.52 for a 1.3B‑parameter model, and also benefits mathematical reasoning after fine‑tuning.

arXiv AI
Aug 11

Full-bandwidth transformer

arXiv:2608. 08888v1 Announce Type: new Abstract: Autoregressive transformers compute along two axes: horizontally across generated tokens, and vertically through model depth.

By Xi Wang, Ziyang Cai, Zheng Zhan, Harry Dong, Ying Fan, Gustavo de Rosa, Tim Pearce, John Langford
arXiv AI
6d ago

How to Loop Your Transformer: Loop Scaling, Specialization, and Parallel Inference

The paper investigates how looping—reusing transformer weights to deepen models without adding parameters—affects performance under different constraints. Experiments on dense decoder‑only transformers up to 1 B parameters show that looping the full transformer yields best quality for a fixed parameter budget, while looping a middle block is preferable when training FLOPs are limited. Adding loop‑specific low‑rank adapters improves quality, but decoding slows linearly with loops; a parallel loop design that passes hidden states across token positions can mitigate this slowdown, though careful handling of token embeddings is needed to retain gains.

By Chanakya Ekbote, Artidoro Pagnoni, Devendra Singh Sachan, Shruti Bhosale, Mike Lewis, Maryam Fazel-Zarandi, Shashank Rajput, Sujan Kumar Gonugondla
arXiv Computation and Language
Oct 27

LoopFold: Parallelizing Recurrent Depth in Looped Transformers

arXiv:2610.35556v1 Announce Type: new Abstract: Looped Transformers increase computation per token by repeatedly applying a shared backbone, offering a way to improve language modeling and downstream...

By Feichen Song, Boyi Zeng, Yiqin Hao, Shixiang Song, He Li, Yizhou Yang, Zitong Wang, Yifan Liu, Ziwei He, Zhouhan Lin
arXiv Machine Learning
Sep 25

FlashLoop: Fast and Memory-Efficient Looped Transformers via Lazy Updates

FlashLoop is a training‑free inference framework for Looped Transformers that reduces cross‑loop redundancy by employing token‑sparse updates, sparse attention, and KV‑residual quantization. It exploits observations that, as loops progress, state changes concentrate on a small token subset, attention differences are dominated by a sparse key subset, and KV residuals become amenable to low‑bit quantization. The method achieves lossless accuracy with up to 1.64× speedup and 6× KV‑cache memory reduction across several Looped Transformer models.

By Wanqi Yang, Shiwei Liu
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
arXiv AI
Oct 2

Closing the Loop: Practical Training Recipes for Looped Language Models

The paper presents practical training recipes for looped language models, showing that a compute‑efficient pipeline can reduce the training budget from 7.7 T tokens to 310 B tokens while maintaining strong reasoning performance. In controlled experiments, a 1.4 B LoopLM outperforms a parameter‑matched dense model on 12 benchmarks, achieving significant gains on GSM8K, MATH, and DROP, and approaches a 3.9 B dense model at matched inference compute. The authors also provide a minimal recipe to convert pretrained dense models into looped ones, demonstrating improvements on Qwen3‑1.7B‑Base across multiple data regimes.

By Andrei Marchenko, Viacheslav Bezrukov, Oleg Kashurin, Inessa Fedorova, Dmitry Bocharov, Yuliana Shakhvalieva, Maria Tikhonova, Valerii Ternovskii
arXiv AI
6d ago

CopyLoop: Fast Looped Transformer Decoding via Context Copying and Shallow Screening

CopyLoop is a training‑free decoding algorithm for looped transformers that speeds up generation by proposing multi‑token suffixes from repeated context, evaluating them early at a shallow recurrent depth, and scheduling continuous recurrent processing. It avoids step‑by‑step decoding, allowing newer blocks to be processed concurrently while earlier blocks continue toward full‑depth verification. Across six model checkpoints from the Ouro, Raven, and Huginn families, CopyLoop delivers 2.98x–10.70x speedups on Base models and 2.74x–3.52x on Thinking models, outperforming or matching all competing baselines on code generation and multi‑step mathematical reasoning tasks.

By Wenyu Du, Stephen Chung
arXiv Computation and Language
Oct 27

StateLoop: Persistent State for Looped Transformers

arXiv:2610.35544v1 Announce Type: new Abstract: Looped Transformers offer a parameter-efficient approach to language modeling by repeatedly applying a shared backbone. Vanilla looped Transformers use...

By Feichen Song, Boyi Zeng, He Li, Shixiang Song, Yiqin Hao, Zitong Wang, Yizhou Yang, Yifan Liu, Ziwei He, Zhouhan Lin