受物理动力学启发,用速度正则化改进Adam,让训练更稳定更快收敛。
A Physics-Inspired Optimizer: Velocity Regularized Adam
- 在Adam基础上加速度惩罚项,大更新时自动降低学习率。
- 实测显示可抑制震荡,使损失下降更平稳,收敛更快。
- 适合追求稳定训练的深度模型开发者,尤其高维优化场景。
我们提出一种受物理启发的优化器——速度正则化Adam(VRAdam),借鉴四阶动能项对系统动力学的稳定作用。现有算法如Adam在训练中常处于自适应稳定性边缘,导致快速振荡和损失收敛变慢。而VRAdam基于速度添加高阶学习率惩罚,当权重更新过大时自动减缓。实际中,有效动态学习率在高速度区间缩小,实现全局阻尼。结合速度正则化与Adam的参数级缩放,形成强大混合优化器。从物理与控制角度,我们对动量机制在稳定性边缘的运作提供严格理论分析,并在温和假设下推导出随机非凸目标下的收敛速率界为$\mathcal{O}(\ln(N)/\sqrt{N})$。实验表明,VRAdam优于标准优化器如AdamW,涵盖图像分类、语言建模、生成建模等任务,使用CNN、Transformer、GFlowNets等多种架构与训练方法。
原文摘要 · Abstract (English)
We introduce Velocity-Regularized Adam (VRAdam), a physics-inspired optimizer for training deep neural networks that draws on ideas from quartic terms for kinetic energy with its stabilizing effects on various system dynamics. Previous algorithms, including the ubiquitous Adam, operate at the so-called adaptive edge of stability regime during training, leading to rapid oscillations and slowed convergence of loss. However, VRAdam adds a higher order penalty on the learning rate based on the velocity such that the algorithm automatically slows down whenever weight updates become large. In practice, we observe that the effective dynamic learning rate shrinks in high-velocity regimes, and damping oscillations. By combining this velocity-based regularizer for global damping with per-parameter scaling of Adam, we create a powerful hybrid optimizer. For this optimizer, we provide rigorous theoretical analysis of operation at the edge of stability from a physical and control perspective for the momentum. Furthermore, we derive convergence bounds with the rate $\mathcal{O}(\ln(N)/\sqrt{N})$ for a stochastic non convex objective under mild assumptions. We demonstrate that VRAdam exceeds the performance against standard optimizers including AdamW. We benchmark various tasks such as image classification, language modeling, and generative modeling using diverse architectures and training methodologies including Convolutional Neural Networks (CNNs), Transformers, and GFlowNets.
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