2020

Momentum via Primal Averaging: Theoretical Insights and Learning Rate Schedules for Non-Convex Optimization

Defazio, Aaron

Understand

Momentum methods are now used pervasively within the machine learning community for training non-convex models such as deep neural networks.

  • Empirically, they out perform traditional stochastic gradient descent (SGD) approaches.
  • In this work we develop a Lyapunov analysis of SGD with momentum (SGD+M), by utilizing a equivalent rewriting of the method known as the stochastic primal averaging (SPA) form.
  • This analysis is much tighter than previous theory in the non-convex case, and due to this we are able to give precise insights into when SGD+M may out-perform SGD, and what hyper-parameter schedules will work and why.

Reading the bibliography…