arXiv Machine Learning
Sep 10

When Does Scale-Invariant Optimization Become Unstable? An Exact Schedule Law with Weight Decay

The paper derives an exact discrete‑time law that captures how learning‑rate schedules and weight decay interact in scale‑invariant neural networks, showing that a single scalar quantity governs the effective step size. It demonstrates that the balance point between contraction and expansion is intrinsically unstable, leading to recurrent dynamics when using constant learning rates with weight decay. The authors extend this analysis to various optimizers and datasets, confirming the law’s precision and showing that performance peaks sharply at the predicted boundary.

By Hasan Amin, Wei-Kai Chang, Rajiv Khanna