这篇论文提出了ReGrad，把梯度当知识存起来，推理时才取用，不破坏原有模型参数，效果比CPT和RAG都好。
论文提出ReGrad（Retrievable Gradients）范式，将梯度视为可检索的知识单元。方法预先离线计算文档特定梯度并存入索引梯度库，推理时仅检索查询相关梯度进行临时权重适应。为解决原始语言建模梯度不适于查询驱动知识使用的问题，引入双层元学习目标重塑梯度为通用适应信号。实验在通用和领域特定设置中表明，ReGrad优于CPT和RAG基线，实现可扩展且可逆的参数化知识注入，不累积权重漂移。
Retrievable Gradients: Continual Post-Training Without Cumulative Weight Drift
Continual post-training enables models to absorb emerging knowledge after deployment, but repeatedly updating shared parameters can accumulate weight drift, potentially causing catastrophic forgetting and degrading general capabilities. Retrieval-augmented generation avoids such parameter drift, yet often lacks the depth of parametric knowledge integration. In this paper, we propose ReGrad (Retrievable Gradients), a new paradigm that treats gradients as retrievable units of knowledge. ReGrad pre-computes document-specific gradients offline, stores them in an indexed Gradient Bank, and retrieves only query-relevant gradients at inference time for temporary weight adaptation. However, raw language-modeling gradients are optimized for token-level document reconstruction rather than for query-driven knowledge use. We therefore introduce a bi-level meta-learning objective that reshapes document-derived gradients into generalizable adaptation signals for downstream tasks. Experiments across general and domain-specific settings show that \textsc{ReGrad} outperforms CPT and RAG baselines, enabling scalable and reversible parametric knowledge injection without accumulating weight drift.