arXiv Computation and Language

Agreement rather than normalisation keeps depth reusable in looped language models

arXiv Computation and Language
Oct 12

One Model to Loop Them All: Elastic Latent Recurrence for Language Models

The paper introduces Elastic Latent Recurrence (ELR), a training recipe that enables looped language models to match the accuracy of non-recurrent models at a single loop while allowing additional loops to improve accuracy with more compute. ELR achieves this through gated state updates with learned step sizes, mixed loop counts during training, and conditioning on loop index and budget. The method also reduces training and inference overhead in Mixture-of-Experts models and produces a single checkpoint, Koi‑4B, that performs competitively with state‑of‑the‑art models on multiple benchmarks.

By Faisal Ladhak, Shantanu Acharya, Santiago Akle Serano, Simeng Sun, Boris Ginsburg, Krishna C Puvvada
arXiv Machine Learning
Oct 8

LayerRoPE: Dynamic Depth-wise Magnitude & Angular Superposition

LayerRoPE introduces a depth‑wise magnitude and angular superposition mechanism that replaces per‑layer normalization gains with a single shared vector and depth‑conditioned scalars, reducing parameters and computational cost. Across 16 pre‑trained large language models and a 100B+ token model ladder, LayerRoPE outperforms traditional Pre‑, Post‑, and Peri‑Norm schemes, achieving comparable or better performance with significantly less compute and improved convergence up to 512 layers. The method demonstrates that widening the residual stream, rather than shrinking it, enhances depth stability and learning‑rate sensitivity, and it transfers effectively to latent and vision transformer architectures.

By Shikhar Srivastava, Christopher Kanan
arXiv Machine Learning
5d ago

There Is No Free Loop: When Does Looping a Trained Model Pay for Its Inference Compute?

The paper investigates whether adding a loop—re‑applying a block of layers—to a trained language model is worth the extra inference cost. Experiments on Qwen3 and Qwen3.5 models from 0.8B to 9B parameters show that only the 0.8B looped model outperforms both a non‑looped model with the same parameters and a model with the same FLOPs. For larger models (4B and 9B), the looped version does not beat the baseline trained without loops, indicating that loops only pay off for small models with a fixed parameter budget.

By Rhea Sanjay Sukthanker, Pashmina Cameron
arXiv AI
Sep 18

Beyond Depth Truncation: Controlled Evaluation of Depth Utilization in Recursive Language Models

The paper critiques the common practice of evaluating depth usage in depth‑recurrent language models by truncating depth during inference and measuring performance decline. It argues that this method conflates three distinct effects—fewer block applications, reduced computation, and an out‑of‑distribution readout—yet is usually interpreted as measuring only the second. To address this, the authors introduce the Depth Control Protocol (DCP), a suite of positive and negative controls that isolate each factor, along with a training intervention to confirm causality, specifically tailored for depth‑wise weight‑sharing architectures.

By Ha Van Dau, Thanh Tung Khuat, Nguyen Thanh Dung
arXiv Machine Learning
Oct 15

Does Depth Survive Composition, and Can a Router Use It? Adaptive Compute in Latent World Models

The paper investigates whether deeper predictor blocks in adaptive‑compute world models truly improve rollout accuracy and whether a router can select the appropriate depth per step. Experiments on nine DeepMind Control tasks show that deeper predictors do not always yield better accuracy, and that a greedy oracle selecting depth per step can reduce error by up to 37% compared to fixed‑depth mixtures, yet no trained router achieves this advantage. The study also finds that supervising early exits only at the first rollout step can mitigate depth‑inversion issues observed in some tasks.

By Achyuthan Sivasankar
arXiv Machine Learning
Sep 4

RecurTrace: Adaptive Latent Reasoning with Loop-Time Memory

RecurTrace introduces adaptive latent reasoning for language models by allowing each looped layer to attend to its own past states and by using a halting head to decide when to stop iterating. This approach overcomes two limitations of prior latent recurrence methods: limited access to earlier computations and a fixed loop count that mismatches input difficulty. In experiments on MathQA, RecurTrace achieves 56.9% accuracy with an average of 2.0 loops, outperforming fixed‑depth baselines and other adaptive methods, and it also improves generation accuracy across a range of model sizes.

By Yuxiang Wang, Kunyu Feng, Yingda Shen, Haoning Xu, Junyu Wang, Zhizheng Wu
arXiv AI
Oct 28

Layerwise Repacking: Variable-Length Hybrid-Attention Training without an Extra Redistribution Pass

The paper introduces Layerwise Repacking, a technique that eliminates an extra data redistribution step when training hybrid‑attention models with variable‑length sequences. By keeping full‑attention layers in wide sequence‑parallel groups (SP16/32) and repacking samples into node‑local sparse children (SP1/2/4/8) within the same all‑to‑all communication, the method preserves hidden‑state continuity and avoids costly inter‑node transfers. Experiments on a 1F3S hybrid‑attention model show that repacking alone cuts end‑to‑end training time by ~6 % and boosts FLOP utilization, with an improved solver further reducing time by ~7.6 % and increasing utilization by ~4.8 %.

By Jiahao Zhang, Junwei Feng, Dongliang Huang, Xiaoling Zhou, Yiqiao Liao, Chengru Song