Discretized Distributed Optimization over Dynamic Digraphs (2311.07939v2)
Abstract: We consider a discrete-time model of continuous-time distributed optimization over dynamic directed-graphs (digraphs) with applications to distributed learning. Our optimization algorithm works over general strongly connected dynamic networks under switching topologies, e.g., in mobile multi-agent systems and volatile networks due to link failures. Compared to many existing lines of work, there is no need for bi-stochastic weight designs on the links. The existing literature mostly needs the link weights to be stochastic using specific weight-design algorithms needed both at the initialization and at all times when the topology of the network changes. This paper eliminates the need for such algorithms and paves the way for distributed optimization over time-varying digraphs. We derive the bound on the gradient-tracking step-size and discrete time-step for convergence and prove dynamic stability using arguments from consensus algorithms, matrix perturbation theory, and Lyapunov theory. This work, particularly, is an improvement over existing stochastic-weight undirected networks in case of link removal or packet drops. This is because the existing literature may need to rerun time-consuming and computationally complex algorithms for stochastic design, while the proposed strategy works as long as the underlying network is weight-symmetric and balanced. The proposed optimization framework finds applications to distributed classification and learning.
- “Distributed estimation approach for tracking a mobile target via formation of UAVs,” IEEE Transactions on Automation Science and Engineering, vol. 19, no. 4, pp. 3765–3776, 2021.
- “Distributed support vector machines over dynamic balanced directed networks,” IEEE Control Systems Letters, vol. 6, pp. 758 – 763, 2021.
- “Optimal CPU scheduling in data centers via a finite-time distributed quantized coordination mechanism,” in 51st IEEE Conf. on Decision and Control, 2021.
- S. Kar and G. Hug, “Distributed robust economic dispatch in power systems: A consensus + innovations approach,” in IEEE Power and Energy Society General Meeting, 2012, pp. 1–8.
- L. Liu and G. Yang, “Distributed fixed-time optimal resource management for microgrids,” IEEE Transactions on Automation Science and Engineering, 2022.
- “A distributed optimization and control framework for a network of constraint coupled residential BESSs,” in IEEE 17th International Conference on Automation Science and Engineering (CASE). IEEE, 2021, pp. 2202–2207.
- M. Doostmohammadian, “Distributed energy resource management: All-time resource-demand feasibility, delay-tolerance, nonlinearity, and beyond,” IEEE Control Systems Letters, 2023.
- T. T. Doan and A. Olshevsky, “Distributed resource allocation on dynamic networks in quadratic time,” Systems & Control Letters, vol. 99, pp. 57–63, 2017.
- “Decentralized optimization over time-varying directed graphs with row and column-stochastic matrices,” IEEE Transactions on Automatic Control, vol. 65, no. 11, pp. 4769–4780, 2020.
- B. Gharesifard and J. Cortés, “Distributed continuous-time convex optimization on weight-balanced digraphs,” IEEE Transactions on Automatic Control, vol. 59, no. 3, pp. 781–786, 2014.
- “ADD-OPT: accelerated distributed directed optimization,” IEEE Trans. on Autom. Control, vol. 63, no. 5, pp. 1329–1339, 2017.
- “Push–pull gradient methods for distributed optimization in networks,” IEEE Transactions on Automatic Control, vol. 66, no. 1, pp. 1–16, 2021.
- “Robust average consensus over packet dropping links: Analysis via coefficients of ergodicity,” in 51st IEEE Conference on Decision and Control, 2012, pp. 2761–2766.
- F. Fagnani and S. Zampieri, “Average consensus with packet drop communication,” SIAM Journal on Control and Optimization, vol. 48, no. 1, pp. 102–133, 2009.
- “Consensusability of multiagent systems with delay and packet dropout under predictor-like protocols,” IEEE Transactions on Automatic Control, vol. 64, no. 8, pp. 3506–3513, 2018.
- Z. Li and J. Chen, “Robust consensus for multi-agent systems communicating over stochastic uncertain networks,” SIAM Journal on Control and Optimization, vol. 57, no. 5, pp. 3553–3570, 2019.
- B. Gerencsér and J. M. Hendrickx, “Push-sum with transmission failures,” IEEE Transactions on Automatic Control, vol. 64, no. 3, pp. 1019–1033, 2018.
- R. Bhatia, Perturbation bounds for matrix eigenvalues, SIAM, 2007.
- K. Rokade and R. K. Kalaimani, “Distributed ADMM over directed networks,” 2021, https://arxiv.org/abs/2010.10421.
- W. Jiang and T. Charalambous, “Distributed alternating direction method of multipliers using finite-time exact ratio consensus in digraphs,” in 2021 European Control Conference (ECC), 2021, pp. 2205–2212.
- “Coordination of groups of mobile autonomous agents using nearest neighbor rules,” IEEE Transactions on automatic control, vol. 48, no. 6, pp. 988–1001, 2003.
- R. Olfati-Saber and R. M. Murray, “Consensus problems in networks of agents with switching topology and time-delays,” IEEE Transactions on Automatic Control, vol. 49, no. 9, pp. 1520–1533, Sept. 2004.
- Multiparameter stability theory with mechanical applications, vol. 13, World Scientific, 2003.
- K. Cai and H. Ishii, “Average consensus on general strongly connected digraphs,” Automatica, vol. 48, no. 11, pp. 2750–2761, 2012.
- G. W. Stewart and J. Sun, “Matrix perturbation theory,” 1990.
- Matrix Analysis, Cambridge University Press, Cambridge, 1985.
- “Consensus-based distributed estimation in the presence of heterogeneous, time-invariant delays,” IEEE Control Systems Letters, vol. 6, pp. 1598 – 1603, 2021.
- J. Cortés, “Discontinuous dynamical systems,” IEEE Control systems magazine, vol. 28, no. 3, pp. 36–73, 2008.
- “Hybrid dynamical systems,” IEEE control systems magazine, vol. 29, no. 2, pp. 28–93, 2009.
- P. Axelsson and F. Gustafsson, “Discrete-time solutions to the continuous-time differential Lyapunov equation with applications to Kalman filtering,” IEEE Transactions on Automatic Control, vol. 60, no. 3, pp. 632–643, 2014.
- “Consensus and cooperation in networked multi-agent systems,” Proceedings of the IEEE, vol. 95, no. 1, pp. 215–233, 2007.
- J. L. Gross and J. Yellen, Handbook of Graph Theory, CRC Press, 2004.
- “Distributed minimum-time weight balancing over digraphs,” in 6th International Symposium on Communications, Control and Signal Processing, May 2014, pp. 190–193.
- “Distributed constraint-coupled optimization over unreliable networks,” in 10th RSI International Conference on Robotics and Mechatronics (ICRoM), Nov 2022.
- “Distributed delay-tolerant strategies for equality-constraint sum-preserving resource allocation,” Systems & Control Letters, vol. 182, pp. 105657, 2023.
- F. Rahimi and R. Mahboobi Esfanjani, “A distributed dual decomposition optimization approach for coordination of networked mobile robots with communication delay,” in 9th RSI International Conference on Robotics and Mechatronics. 2021, pp. 18–23, IEEE.
- “1st-order dynamics on nonlinear agents for resource allocation over uniformly-connected networks,” in IEEE Conference on Control Technology and Applications (CCTA), 2022, pp. 1184–1189.