arXiv Machine Learning

TANDEM: Bi-Level Data Mixture Optimization with Twin Networks

arXiv:2606. 04401v1 Announce Type: new Abstract: The capabilities of large language models (LLMs) significantly depend on training data drawn from various domains.

arXiv Machine Learning
Oct 3

SLIM: Simplex-Lattice Interpolation Merging

The paper introduces Simplex-Lattice Interpolation Merging (SLIM), a method that builds a quadratic surrogate model of aggregate performance over merging coefficients for large language models using a classical mixture design. By evaluating only individual experts and equal-weight pairs, SLIM identifies the surrogate with the fewest measurements needed and then optimizes it without further target-metric evaluations. Experiments on two model architectures show that SLIM accurately predicts unseen multi-expert mixtures and achieves competitive merge performance under limited evaluation budgets, outperforming random designs and regularized fitting.

By Seongcheol Jeong, Masahiro Suzuki, Yutaka Matsuo
arXiv Computation and Language
Oct 1

DataFlex: A Unified Framework for Data-Centric Dynamic Training of Large Language Models

arXiv:2603.26164v2 Announce Type: replace-cross Abstract: Data-centric training has emerged as a promising direction for improving large language models (LLMs) by optimizing not only model parameters...

By Hao Liang, Zhengyang Zhao, Mingrui Chen, Meiyi Qiang, Lu Ma, Rongyi Yu, Hengyi Feng, Shixuan Sun, Zimo Meng, Xiaochen Ma, Xuanlin Yang, Qifeng Cai, Ruichuan An, Bohan Zeng, Zhen Hao Wong, Chengyu Shen, Runming He, Zhaoyang Han, Yaowei Zheng, Fangcheng Fu, Conghui He, Bin Cui, Zhiyu Li, Weinan E, Wentao Zhang
arXiv AI
Aug 26

Data Mixing as Mixture Experiment: Response Surface Methodology and Optimal Design for Large Language Model Pretraining

The article proposes treating large language model (LLM) data mixing as a classical mixture experiment, where data domains are components, token shares are proportions, and proxy-training runs serve as design points. Using sparse second‑order Scheffé response‑surface models, the authors construct model‑robust Σ‑optimal designs that efficiently identify optimal data mixtures and reveal strong interaction effects, especially between weak domains and web‑derived text. Empirical results on RegMix show that these designs recover mixture rankings while reducing proxy runs by about 25%, demonstrating that data mixing can be optimized through experimental design rather than solely prediction.

By Yicheng Mao, Hongru Du
arXiv Machine Learning
Aug 28

Squeezing More from Limited Data with Recursive Transformers

The paper investigates how to effectively pre‑train language models when the data budget is limited but compute is plentiful. It shows that increasing model size only improves performance up to an optimal point, after which overfitting degrades generalization, and that this optimal size varies with both the data budget and downstream tasks. To overcome the inefficiencies of standard Transformers in this regime, the authors propose recursive Transformers that reuse a shared block across depth and employ factorized embeddings, achieving better results than standard models on 10M–100M word pre‑training budgets and competitive performance with BabyLM Challenge 2025 winners.

By Serdar G\"ulbahar, Lukas Edman, Alexander Fraser
arXiv Machine Learning
Sep 11

Data Scarcity and Model Sparsity: Mixtures-of-Experts Overfit More to Repeated Data

The paper investigates how data repetition affects Mixture-of-Experts (MoE) language models compared to dense Transformers. Across models from 80 M to 1 B active parameters, MoEs degrade more quickly as data is repeated, with performance dropping significantly beyond 4× repetition and overtaking dense models only when strong regularization is applied. The study also identifies routing stabilization and expert specialization as key factors in MoE overfitting, and explores regularization techniques that can partially mitigate this issue.

By Atindra Jha, Margaret Li, Jure Leskovec, Percy Liang, Luke Zettlemoyer