GAC: Noise-Aware Adaptive Mixing for Hybrid SFT-RL Post-Training

Fuente: arXiv
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Auteurs principaux: Hu, Yuelin, Yu, Zhenbo, Cheng, Zhengxue, Liu, Wei, Song, Li
Format: Preprint
Publié: 2026
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author Hu, Yuelin
Yu, Zhenbo
Cheng, Zhengxue
Liu, Wei
Song, Li
author_facet Hu, Yuelin
Yu, Zhenbo
Cheng, Zhengxue
Liu, Wei
Song, Li
contents Hybrid post-training usually combines supervised fine-tuning and reinforcement learning, but fixed mixing schedules cannot adapt when the relative noise of the two signals changes over time. We propose GAC, a noise-aware controller that derives an adaptive mixing weight from online estimates of gradient variance and disagreement between the two training signals. The method adds smoothing, prior guidance, and bounded updates while reusing existing training tensors. Experiments on math, code, science, and logic benchmarks show that GAC consistently improves hybrid post-training over strong fixed and rule-based baselines, with larger gains at larger model scales and less than 1% training overhead.
format Preprint
id arxiv_https___arxiv_org_abs_2605_26184
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle GAC: Noise-Aware Adaptive Mixing for Hybrid SFT-RL Post-Training
Hu, Yuelin
Yu, Zhenbo
Cheng, Zhengxue
Liu, Wei
Song, Li
Machine Learning
Artificial Intelligence
Hybrid post-training usually combines supervised fine-tuning and reinforcement learning, but fixed mixing schedules cannot adapt when the relative noise of the two signals changes over time. We propose GAC, a noise-aware controller that derives an adaptive mixing weight from online estimates of gradient variance and disagreement between the two training signals. The method adds smoothing, prior guidance, and bounded updates while reusing existing training tensors. Experiments on math, code, science, and logic benchmarks show that GAC consistently improves hybrid post-training over strong fixed and rule-based baselines, with larger gains at larger model scales and less than 1% training overhead.
title GAC: Noise-Aware Adaptive Mixing for Hybrid SFT-RL Post-Training
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2605.26184