AFL: A Single-Round Analytic Approach for Federated Learning with Pre-trained Models
Run He, Kai Tong, Di Fang, Han Sun, Haoran Li, Tianyi Chen, Ziqian Zeng, Huiping Zhuang
TL;DR
AFL presents a gradient-free federated learning framework that uses a pre-trained backbone to convert client training into a closed-form linear regression solved in one epoch, paired with an Absolute Aggregation law that enables single-round, optimal aggregation across clients. The Regularization Intermediary (RI) handles rank-deficient cases, preserving the AA-law's exact equivalence to centralized training. The approach exhibits invariance to data partitioning and client count, delivers fast convergence, and achieves competitive accuracy across extremely non-IID settings and large client populations, with substantial communication and computation savings. The method is validated on CIFAR-10/100 and Tiny-ImageNet with multiple backbones, and the authors provide public code for reproducibility.
Abstract
In this paper, we introduce analytic federated learning (AFL), a new training paradigm that brings analytical (i.e., closed-form) solutions to the federated learning (FL) with pre-trained models. Our AFL draws inspiration from analytic learning -- a gradient-free technique that trains neural networks with analytical solutions in one epoch. In the local client training stage, the AFL facilitates a one-epoch training, eliminating the necessity for multi-epoch updates. In the aggregation stage, we derive an absolute aggregation (AA) law. This AA law allows a single-round aggregation, reducing heavy communication overhead and achieving fast convergence by removing the need for multiple aggregation rounds. More importantly, the AFL exhibits a property that $\textit{invariance to data partitioning}$, meaning that regardless of how the full dataset is distributed among clients, the aggregated result remains identical. This could spawn various potentials, such as data heterogeneity invariance and client-number invariance. We conduct experiments across various FL settings including extremely non-IID ones, and scenarios with a large number of clients (e.g., $\ge 1000$). In all these settings, our AFL constantly performs competitively while existing FL techniques encounter various obstacles. Our codes are available at https://github.com/ZHUANGHP/Analytic-federated-learning.
