Reasoning-preserved Efficient Distillation of Large Language Models via Activation-aware Initialization

Fuente: arXiv
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Autores principales: He, Junlin, Tang, Yihong, Nie, Tong, Li, Guilong, Yang, Binyu, Du, Jinxiao, Sun, Lijun, Ma, Wei
Formato: Preprint
Publicado: 2026
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author He, Junlin
Tang, Yihong
Nie, Tong
Li, Guilong
Yang, Binyu
Du, Jinxiao
Sun, Lijun
Ma, Wei
author_facet He, Junlin
Tang, Yihong
Nie, Tong
Li, Guilong
Yang, Binyu
Du, Jinxiao
Sun, Lijun
Ma, Wei
contents Efficient Distillation (EDistill) compresses large language models (LLMs) by structured pruning parameters and tuning lightweight modules with high training efficiency. Although these EDistilled LLMs achieve state-of-the-art (SOTA) performance on general ability benchmarks relative to similarly sized LLMs, we identify a severe degradation in their multi-step reasoning ability, which we term reasoning collapse. We systematically analyze the geometric origins of reasoning collapse and show that the SOTA EDistill method based on width-reducing projection matrices suffers from eRank collapse, in which the effective rank (eRank) of hidden representations drops. We theoretically explain how singular values of randomly initialized projection matrices become unevenly distributed, leading to eRank collapse and thus token indistinguishability. To address this issue, we propose RED (Reasoning-preserved Efficient Distillation) for LLMs, which introduces activation-aware initialization to initialize projection matrices as channel-selection matrices, thus theoretically mitigating eRank collapse. Experiments on Llama and Qwen series demonstrate that RED substantially recovers reasoning while maintaining high training efficiency and SOTA general ability.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29327
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Reasoning-preserved Efficient Distillation of Large Language Models via Activation-aware Initialization
He, Junlin
Tang, Yihong
Nie, Tong
Li, Guilong
Yang, Binyu
Du, Jinxiao
Sun, Lijun
Ma, Wei
Computation and Language
Machine Learning
Efficient Distillation (EDistill) compresses large language models (LLMs) by structured pruning parameters and tuning lightweight modules with high training efficiency. Although these EDistilled LLMs achieve state-of-the-art (SOTA) performance on general ability benchmarks relative to similarly sized LLMs, we identify a severe degradation in their multi-step reasoning ability, which we term reasoning collapse. We systematically analyze the geometric origins of reasoning collapse and show that the SOTA EDistill method based on width-reducing projection matrices suffers from eRank collapse, in which the effective rank (eRank) of hidden representations drops. We theoretically explain how singular values of randomly initialized projection matrices become unevenly distributed, leading to eRank collapse and thus token indistinguishability. To address this issue, we propose RED (Reasoning-preserved Efficient Distillation) for LLMs, which introduces activation-aware initialization to initialize projection matrices as channel-selection matrices, thus theoretically mitigating eRank collapse. Experiments on Llama and Qwen series demonstrate that RED substantially recovers reasoning while maintaining high training efficiency and SOTA general ability.
title Reasoning-preserved Efficient Distillation of Large Language Models via Activation-aware Initialization
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2605.29327