Skip to yearly menu bar Skip to main content


Poster

Solving Non-smooth Constrained Programs with Lower Complexity than O(1/ε): A Primal-Dual Homotopy Smoothing Approach

Xiaohan Wei · Hao Yu · Qing Ling · Michael Neely

Keywords: [ Convex Optimization ] [ Computational Complexity ] [ Distributed Inference ]

[ ]
[ Paper
2018 Poster

Abstract: We propose a new primal-dual homotopy smoothing algorithm for a linearly constrained convex program, where neither the primal nor the dual function has to be smooth or strongly convex. The best known iteration complexity solving such a non-smooth problem is O(ε1). In this paper, we show that by leveraging a local error bound condition on the dual function, the proposed algorithm can achieve a better primal convergence time of O\l(ε2/(2+β)log2(ε1)\r), where β(0,1] is a local error bound parameter. As an example application, we show that the distributed geometric median problem, which can be formulated as a constrained convex program, has its dual function non-smooth but satisfying the aforementioned local error bound condition with β=1/2, therefore enjoying a convergence time of O\l(ε4/5log2(ε1)\r). This result improves upon the O(ε1) convergence time bound achieved by existing distributed optimization algorithms. Simulation experiments also demonstrate the performance of our proposed algorithm.

Chat is not available.