Comment by hodgehog11
12 hours ago
No, I have to push back as well, sorry. It takes a very long time to get to the "near-minimizer" stage when training a neural network, and in practice, you never get there (see neural scaling law regimes). What you are saying is the viewpoint from 6-7 years ago. Things have changed.
The reasons why optimizers work well for neural networks in their highly nonconvex landscapes has absolutely nothing to do with their performance in convex landscapes. If that were true, everyone would be using Newton-CG. These optimizers were born in the convex optimization literature as a consequence of the genetic optimization nature of incremental publication (and because that was all we had), but their modern study is through the lens of implicit regularization (their preferences for certain minima) and their stepwise vs. continuous rates for feature learning in multilayer models.
This is completely new theory by the way, and requires painful reinvention of the field. It does not stand on the shoulders of convex optimization. The nonconvex setting is assuredly not a perturbation of the convex setting, and those that do continue to work on deep learning optimization from the convex optimization perspective are well behind the times.
It seems that we have two different stories here: in one, the new optimization theory represents a stark departure from the prior art, a sort of revolutionary new view of the understanding of optimization as applied to neural networks.
In the other story, the current understanding of optimization is a natural evolution of past work, where a new generation of researchers respond to social and technological changes, adapting and building on the work of the past, taking what's useful, downplaying the importance of some ideas, and inventing new language to describe concepts that seem most relevant to the current situation.
Both stories tell some of the truth. A revolution or evolution? Looking at the literature (eg the sibling comment here) shows that even today, convexity is used as an intuition pump for modern optimization techniques. But there are also new ideas that apply to the specific exigencies of neural nets, and downplayed ideas (eg convergence rates) that seem less relevant.
If people want to learn more, at ICML (one of the top AI/ML conferences) this year there was a whole tutorial on this topic: https://www.cs.ubc.ca/~schmidtm/Documents/2026_ICML_Tutorial...