Self-concordant inclusions: A unified framework for path-following generalized Newton-type algorithms

We study a class of monotone inclusions called “self-concordant inclusion” which covers three fundamental convex optimization formulations as special cases. We develop a new generalized Newton-type framework to solve this inclusion. Our framework subsumes three schemes: full-step, damped-step and path-following methods as specific instances, while allows one to use inexact computation to form generalized Newton directions. We prove a local quadratic convergence of both the full-step and damped-step algorithms. Then, we propose a new two-phase inexact path-following scheme for solving this monotone inclusion which possesses an O(√ν log(1/ε))-worst-case iteration-complexity to achieve an ε-solution, where ν is the barrier parameter and ε is a desired accuracy. As byproducts, we customize our scheme to solve three convex problems: convex-concave saddle-point, nonsmooth constrained convex program, and nonsmooth convex program with linear constraints. We also provide three numerical examples to illustrate our theory and compare with existing methods.

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