Towards Efficient LLMs Annealing with Principled Sample Selection

Fuente: arXiv
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Main Authors: Xu, Yuanjian, Hao, Jianing, Zhang, Wanbo, Li, Zhong, Zhang, Guang
Format: Preprint
Published: 2026
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author Xu, Yuanjian
Hao, Jianing
Zhang, Wanbo
Li, Zhong
Zhang, Guang
author_facet Xu, Yuanjian
Hao, Jianing
Zhang, Wanbo
Li, Zhong
Zhang, Guang
contents The annealing phase is a pivotal convergence stage in LLM pre-training that ultimately determines final model quality. However, effectively selecting training data during this phase remains a key challenge. Current strategies rely on empirical heuristics, such as domain filtering or context extension, which lack a principled grounding in optimization theory. In this work, we characterize the annealing phase through the lens of the loss landscape's spectral geometry. We argue that optimal convergence requires gradient updates to satisfy heterogeneous constraints across different eigen-directions. Building on this insight, we formulate data selection as a problem of satisfying these directional constraints. To this end, we propose DiReCT (Directionally-Restrained Constrained Training), a novel framework that reformulates sample selection in the annealing stage as a constrained optimization problem. By imposing explicit directional constraints on per-sample gradients based on the spectral properties of the Hessian, DiReCT identifies samples that align with the optimal curvature-aware descent path. Extensive experiments across various model scales demonstrate that DiReCT consistently achieves state-of-the-art performance. For future research, code is available at https://github.com/xuyj233/Direct.
format Preprint
id arxiv_https___arxiv_org_abs_2605_31175
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Towards Efficient LLMs Annealing with Principled Sample Selection
Xu, Yuanjian
Hao, Jianing
Zhang, Wanbo
Li, Zhong
Zhang, Guang
Computation and Language
The annealing phase is a pivotal convergence stage in LLM pre-training that ultimately determines final model quality. However, effectively selecting training data during this phase remains a key challenge. Current strategies rely on empirical heuristics, such as domain filtering or context extension, which lack a principled grounding in optimization theory. In this work, we characterize the annealing phase through the lens of the loss landscape's spectral geometry. We argue that optimal convergence requires gradient updates to satisfy heterogeneous constraints across different eigen-directions. Building on this insight, we formulate data selection as a problem of satisfying these directional constraints. To this end, we propose DiReCT (Directionally-Restrained Constrained Training), a novel framework that reformulates sample selection in the annealing stage as a constrained optimization problem. By imposing explicit directional constraints on per-sample gradients based on the spectral properties of the Hessian, DiReCT identifies samples that align with the optimal curvature-aware descent path. Extensive experiments across various model scales demonstrate that DiReCT consistently achieves state-of-the-art performance. For future research, code is available at https://github.com/xuyj233/Direct.
title Towards Efficient LLMs Annealing with Principled Sample Selection
topic Computation and Language
url https://arxiv.org/abs/2605.31175