On the Maximum Hessian Eigenvalue and Generalization

التفاصيل البيبلوغرافية
العنوان: On the Maximum Hessian Eigenvalue and Generalization
المؤلفون: Kaur, Simran, Cohen, Jeremy, Lipton, Zachary C.
سنة النشر: 2022
المجموعة: Computer Science
Statistics
مصطلحات موضوعية: Computer Science - Machine Learning, Statistics - Machine Learning
الوصف: The mechanisms by which certain training interventions, such as increasing learning rates and applying batch normalization, improve the generalization of deep networks remains a mystery. Prior works have speculated that "flatter" solutions generalize better than "sharper" solutions to unseen data, motivating several metrics for measuring flatness (particularly $\lambda_{max}$, the largest eigenvalue of the Hessian of the loss); and algorithms, such as Sharpness-Aware Minimization (SAM) [1], that directly optimize for flatness. Other works question the link between $\lambda_{max}$ and generalization. In this paper, we present findings that call $\lambda_{max}$'s influence on generalization further into question. We show that: (1) while larger learning rates reduce $\lambda_{max}$ for all batch sizes, generalization benefits sometimes vanish at larger batch sizes; (2) by scaling batch size and learning rate simultaneously, we can change $\lambda_{max}$ without affecting generalization; (3) while SAM produces smaller $\lambda_{max}$ for all batch sizes, generalization benefits (also) vanish with larger batch sizes; (4) for dropout, excessively high dropout probabilities can degrade generalization, even as they promote smaller $\lambda_{max}$; and (5) while batch-normalization does not consistently produce smaller $\lambda_{max}$, it nevertheless confers generalization benefits. While our experiments affirm the generalization benefits of large learning rates and SAM for minibatch SGD, the GD-SGD discrepancy demonstrates limits to $\lambda_{max}$'s ability to explain generalization in neural networks.
Comment: Proceedings on "I Can't Believe It's Not Better! - Understanding Deep Learning Through Empirical Falsification" at NeurIPS 2022 Workshops, PMLR 187:51-65, 2023
نوع الوثيقة: Working Paper
URL الوصول: http://arxiv.org/abs/2206.10654
رقم الأكسشن: edsarx.2206.10654
قاعدة البيانات: arXiv