Fast primal-dual algorithms via dynamics for linearly constrained convex optimization problems

By time discretization of a primal-dual dynamical system, we propose an inexact primal-dual algorithm, linked to the Nesterov's acceleration scheme, for the linear equality constrained convex optimization problem. We also consider an inexact linearized primal-dual algorithm for the composite problem with linear constrains. Under suitable conditions, we show that these algorithms enjoy fast convergence properties. Finally, we study the convergence properties of the primal-dual dynamical system to better understand the accelerated schemes of the proposed algorithms. We also report numerical experiments to demonstrate the effectiveness of the proposed algorithms

Fast convergence of primal-dual dynamics and algorithms with time scaling for linear equality constrained convex optimization problems

We propose a primal-dual dynamic with time scaling for a linear equality constrained convex optimization problem, which consists of a second-order ODE for the primal variable and a first-order ODE for the dual variable. Without assuming strong convexity, we prove its fast convergence property and show that the obtained fast convergence property is preserved under a small perturbation. We also develop an inexact primal-dual algorithm derived by a time discretization, and derive the fast convergence property matching that of the underlying dynamic. Finally, we give numerical experiments to illustrate the validity of the proposed algorithm