A Stochastic Newton Algorithm for Distributed Convex Optimization
summary
A distributed stochastic Newton algorithm for homogeneous convex problems introduces a stochastic Hessian-vector product oracle and solves constrained quadratic subproblems by running local SGD for k inner iterations between R communication rounds. The method proves convergence for quasi-self-concordant objectives (e.g., logistic regression), reduces the number and frequency of communication rounds versus prior methods, matches lower bounds in limited-communication regimes under assumptions, and shows empirical wins in the low-communication setting.
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chapters (19)
- 0:00Large-scale optimization intro
- 1:30Stochastic gradient descent & higher-order methods
- 3:40Distributed optimization & bottlenecks
- 5:29Federated Stochastic Newton overview
- 6:54Optimization setup & assumptions
- 8:20Convex & smooth formulation
- 10:48Communication structure
- 12:18Local SGD & quadratic benefits
- 14:28Newton’s method & second-order info
- 16:17Quadratic subproblems & Hessian products
- 18:27Stochastic Hessian-vector oracle
- 19:34Quasi-self-concordance condition
- 21:29Method design & constrained minimization
- 22:59Convergence guarantees
- 24:00Comparison with FedAc & bounds
- 26:15Empirical results & efficiency
- 27:39Open problems & future work
- 29:06Conclusion
- 29:52Q&A
