Mastering Text, Code and Math Simultaneously via Fusing Highly Specialized Language Models
Ning Ding, Yulin Chen, Ganqu Cui, Xingtai Lv, Weilin Zhao, Ruobing Xie, Bowen Zhou, Zhiyuan Liu, Maosong Sun
TL;DR
UltraFuser addresses the challenge of achieving simultaneous proficiency across text, code, and math by fusing three domain-specialized LLMs through a token-level gating mechanism. It introduces a two-stage training procedure with balanced data sampling and a high-quality instruction-tuning dataset, UltraChat 2, to align the fused model with multi-domain tasks. Empirical results across language, code, and math benchmarks show that the fused model can outperform individual specialists and naive joint training, demonstrating the viability and benefits of explicit specialist fusion for broad-domain expertise. The work provides a practical framework and resources for integrating specialized capabilities into general-purpose interactive systems, with implications for multi-domain AI tooling and future extensions to additional symbol systems.
Abstract
Underlying data distributions of natural language, programming code, and mathematical symbols vary vastly, presenting a complex challenge for large language models (LLMs) that strive to achieve high performance across all three domains simultaneously. Achieving a very high level of proficiency for an LLM within a specific domain often requires extensive training with relevant corpora, which is typically accompanied by a sacrifice in performance in other domains. In this paper, we propose to fuse models that are already highly-specialized directly. The proposed fusing framework, UltraFuser, consists of three distinct specialists that are already sufficiently trained on language, coding, and mathematics. A token-level gating mechanism is introduced to blend the specialists' outputs. A two-stage training strategy accompanied by balanced sampling is designed to ensure stability. To effectively train the fused model, we further construct a high-quality supervised instruction tuning dataset, UltraChat 2, which includes text, code, and mathematical content. This dataset comprises approximately 300,000 instructions and covers a wide range of topics in each domain. Experiments show that our model could simultaneously achieve mastery of the three crucial domains.
