arXiv Computation and Language

LinMix: Data Mixing as Linear Domain Attribution

LinMix proposes a hyperparameter‑free vertex sampling strategy for data mixing in language model pretraining, treating domain attribution as a linear regression problem. By sampling mixes at the vertices of a capped simplex, it decorrelates domain effects and yields an interpretable linear model whose coefficients directly reflect each domain’s contribution. Experiments on 1B‑parameter OLMo2 and 4B Qwen3.5 models demonstrate that LinMix outperforms traditional Dirichlet‑based mixing, achieving significant gains on reasoning, code, and math benchmarks and improving overall accuracy by 11% on average over the best nonlinear baseline.

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 AI
Oct 28

An Embarrassingly Simple Data Selection Strategy for Million-Scale Multi-Modal Instruction-Tuning

The paper introduces SSR, a simple yet effective data selection strategy for million‑scale multi‑modal instruction‑tuning. SSR uses interaction styles as a proxy for structural diversity and decomposes data quality into capability‑specific scores, forming a rich profile for each sample. By casting selection as submodular coverage maximization, SSR consistently outperforms random sampling across two architecture stacks, multiple data pools, and 14 benchmarks, achieving 99.1% of full‑data performance with only 30% of a 2.6M pool.

By Mengyao Lyu, Yan Li, Huasong Zhong, Hui Chen, Jungong Han, Guiguang Ding, Zhenheng Yang
arXiv Machine Learning
Oct 16

INCONVENIENT: A Benchmark to Assess LLM Generalization Capabilities from Convenience Samples

INCONVENIENT is a new benchmark that evaluates how machine‑learning models, especially large language models, generalize when trained on convenience samples that bias feature–target relationships. Unlike prior distribution‑shift tests that rely on natural domain splits, INCONVENIENT explicitly perturbs these relationships while keeping the deployment population unchanged, allowing controlled study of shift severity and direction. The benchmark covers 200 tabular classification and regression datasets and produces about 15,500 shifted training distributions, revealing significant performance degradation.

By Sara Rezaeimanesh, Chad Klochko, Kundan Thind, Mohammad Ghassemi
arXiv Computation and Language
Oct 12

Probabilistic Calibration Is a Trainable Capability in Language Models

The paper investigates whether language models can be fine‑tuned to produce outputs that better match intended probability distributions, even when the valid outputs cannot be enumerated in advance. Two calibration fine‑tuning methods—soft‑target and hard‑target—are evaluated across 12 models from four families, showing substantial improvements in structured‑sampling fidelity on unseen distribution families and parameter settings. The gains also transfer to broader stochastic generation tasks, expanding first‑token support and improving NoveltyBench scores, though some downstream capabilities such as arithmetic reasoning may be slightly affected.

By Davide Baldelli, Sruthi Kuriakose, Maryam Hashemzadeh, Amal Zouaq, Sarath Chandar
arXiv AI
Jun 26

Limited Reference, Reliable Generation: A Two-Component Framework for Tabular Data Generation in Low-Data Regimes

arXiv:2509. 09960v2 Announce Type: replace-cross Abstract: Synthetic tabular data generation is increasingly essential in machine learning, supporting downstream applications when real-world, high-quality tabular data is insufficient.

By Mingxuan Jiang, Keyang Chen, Yongxin Wang, Yongsheng Zhao, Ziyue Dai, Yicun Liu, Zeping Li, Qiuyang Zhang, Hongyi Nie, Hongbin Zhu, Sen Liu, Guangnan Ye, Hongfeng Chai
arXiv AI
Oct 15

Match the Canvas, Not Just the Answer: Predictability-Aware SFT for Diffusion Language Models

The paper introduces Predictability-Aware Canvas Selection and Supervision (PACS), a supervised fine‑tuning method for diffusion language models that aligns training with inference by using the model’s own predictability to determine which tokens are visible and when they are supervised. PACS selects the attention‑visible input length for each example and supervises reference tokens just before they become confident, addressing mismatches caused by random masking. Experiments on reasoning and code‑generation benchmarks show PACS consistently outperforms standard SFT, achieving up to 12.84 percentage‑point gains on individual tasks.

By Miao Li, Hanyang Jiang, Hengyu Fu, Baihe Huang, Yating Liu, Yuhang Cai, Changkun Guan, Zhongzhu Chen, Jiecheng Lu, Michael A. Boateng, Pascal Van Hentenryck