arXiv:2603.21991cs.LGcs.AI2026-03

通过可学习的参数控制GELU门控硬度,实现平滑训练到ReLU模型的可控转换。

$λ$-GELU: Learning Gating Hardness for Controlled ReLU-ization in Deep Networks

  • 提出λ-GELU模型,用参数λ调控门控函数陡度,实现平滑激活向ReLU的渐进转化。
  • 实验显示不同层具有结构化硬度分布,且对初始化鲁棒,验证了可调控性。
  • 支持训练后无损替换为ReLU,适合需兼容传统推理工具链的部署场景。

Gaussian Error Linear Unit(GELU)是广泛使用的平滑替代ReLU的激活函数,但许多部署、压缩和分析工具链更自然地适用于分段线性(ReLU型)网络。本文研究一种基于硬度参数λ的GELU形式:f(x;λ)=xΦ(λx),其中Φ为标准正态累积分布函数,λ∈[1,∞)控制门控陡度。目标是将平滑的门控训练转化为通向可兼容ReLU模型的可控路径。学习λ存在挑战:直接更新导致动态不稳定与有效梯度衰减,因此引入约束重参数化与优化器感知更新策略。在涵盖MLP、CNN和Transformer的多种模型-数据集组合上,观察到分层的结构化硬度分布,并评估其在不同初始化下的鲁棒性。进一步研究了一种确定性ReLU化策略:逐步硬化学习到的门控,逼近一个原则性目标,实现训练后λ-GELU到ReLU的低扰动替换。总体而言,λ-GELU提供了一个最小且可解释的调控旋钮,连接平滑训练与以ReLU为中心的下游流程。

原文摘要 · Abstract (English)

Gaussian Error Linear Unit (GELU) is a widely used smooth alternative to Rectifier Linear Unit (ReLU), yet many deployment, compression, and analysis toolchains are most naturally expressed for piecewise-linear (ReLU-type) networks. We study a hardness-parameterized formulation of GELU, f(x;λ)=xΦ(λ x), where Φ is the Gaussian CDF and λ \in [1, infty) controls gate sharpness, with the goal of turning smooth gated training into a controlled path toward ReLU-compatible models. Learning λ is non-trivial: naive updates yield unstable dynamics and effective gradient attenuation, so we introduce a constrained reparameterization and an optimizer-aware update scheme. Empirically, across a diverse set of model--dataset pairs spanning MLPs, CNNs, and Transformers, we observe structured layerwise hardness profiles and assess their robustness under different initializations. We further study a deterministic ReLU-ization strategy in which the learned gates are progressively hardened toward a principled target, enabling a post-training substitution of λ-GELU by ReLU with reduced disruption. Overall, λ-GELU provides a minimal and interpretable knob to profile and control gating hardness, bridging smooth training with ReLU-centric downstream pipelines.

激活函数可微替换模型部署

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