# Understanding A Class of Decentralized and Federated Optimization Algorithms: A Multi-Rate Feedback Control Perspective

arXiv: https://arxiv.org/abs/2204.12663 · HTML: https://mlsanity.com/paper/2204.12663/

## Key facts

- Cited by 2 papers in the map (data through 14 Oct 2026).
- Builds on 22 of its 36 references that are in the map.
- First posted on arXiv 27 Apr 2022.

## Builds on (most cited first, 22 of 22)

- [Federated Optimization in Heterogeneous Networks](https://mlsanity.com/paper/1812.06127/) (2018)
- [Federated Learning: Challenges, Methods, and Future Directions](https://mlsanity.com/paper/1908.07873/) (2019)
- [On the Convergence of FedAvg on Non-IID Data](https://mlsanity.com/paper/1907.02189/) (2019)
- [Adaptive Federated Optimization](https://mlsanity.com/paper/2003.00295/) (2020)
- [Towards Federated Learning at Scale: System Design](https://mlsanity.com/paper/1902.01046/) (2019)
- [On the Convergence of Decentralized Gradient Descent](https://mlsanity.com/paper/1310.7063/) (2013)
- [FedPD: A Federated Learning Framework with Optimal Rates and Adaptivity to Non-IID Data](https://mlsanity.com/paper/2005.11418/) (2020)
- [NEXT: In-Network Nonconvex Optimization](https://mlsanity.com/paper/1602.00591/) (2016)
- [Analysis and Design of Optimization Algorithms via Integral Quadratic Constraints](https://mlsanity.com/paper/1408.3595/) (2014)
- [Optimal algorithms for smooth and strongly convex distributed optimization in networks](https://mlsanity.com/paper/1702.08704/) (2017)
- [First Analysis of Local GD on Heterogeneous Data](https://mlsanity.com/paper/1909.04715/) (2019)
- [A decentralized proximal-gradient method with network independent step-sizes and separated convergence rates](https://mlsanity.com/paper/1704.07807/) (2017)
- [A Dynamical Systems Perspective on Nesterov Acceleration](https://mlsanity.com/paper/1905.07436/) (2019)
- [A geometric alternative to Nesterov's accelerated gradient descent](https://mlsanity.com/paper/1506.08187/) (2015)
- [Multi-consensus Decentralized Accelerated Gradient Descent](https://mlsanity.com/paper/2005.00797/) (2020)
- [Continuous-time Models for Stochastic Optimization Algorithms](https://mlsanity.com/paper/1810.02565/) (2018)
- [Can Primal Methods Outperform Primal-dual Methods in Decentralized Dynamic Optimization?](https://mlsanity.com/paper/2003.00816/) (2020)
- [Control Interpretations for First-Order Optimization Methods](https://mlsanity.com/paper/1703.01670/) (2017)
- [Distributed Non-Convex First-Order Optimization and Information Processing: Lower Complexity Bounds and Rate Optimal Algorithms](https://mlsanity.com/paper/1804.02729/) (2018)
- [Distributed Gradient Flow: Nonsmoothness, Nonconvexity, and Saddle Point Evasion](https://mlsanity.com/paper/2008.05387/) (2020)
- [Continuous-time Proportional-Integral Distributed Optimization for Networked Systems](https://mlsanity.com/paper/1309.6613/) (2013)
- [Distributed Gradient Descent: Nonconvergence to Saddle Points and the Stable-Manifold Theorem](https://mlsanity.com/paper/1908.02747/) (2019)

## Built on by (most cited first, 2 of 2)

- [DiSK: Differentially Private Optimizer with Simplified Kalman Filter for Noise Reduction](https://mlsanity.com/paper/2410.03883/) (2024)
- [Review of Mathematical Optimization in Federated Learning](https://mlsanity.com/paper/2412.01630/) (2024)

## Abstract (arXiv)

Distributed algorithms have been playing an increasingly important role in many applications such as machine learning, signal processing, and control. Significant research efforts have been devoted to developing and analyzing new algorithms for various applications. In this work, we provide a fresh perspective to understand, analyze, and design distributed optimization algorithms. Through the lens of multi-rate feedback control, we show that a wide class of distributed algorithms, including popular decentralized/federated schemes, can be viewed as discretizing a certain continuous-time feedback control system, possibly with multiple sampling rates, such as decentralized gradient descent, gradient tracking, and federated averaging. This key observation not only allows us to develop a generic framework to analyze the convergence of the entire algorithm class. More importantly, it also leads to an interesting way of designing new distributed algorithms. We develop the theory behind our framework and provide examples to highlight how the framework can be used in practice.
