A Unified Splitting Algorithm for Composite Monotone Inclusions

Operator splitting methods have been recently concerned with inclusions problems based on composite operators made of the sum of two monotone operators, one of them associated with a linear transformation. We analyze here a general and new splitting method which indeed splits both operator proximal steps, and avoiding costly numerical algebra on the linear operator. The family of algorithms induced by our generalized setting includes known methods like Chambolle-Pock primal-dual algorithm and Shefi-Teboulle Proximal Alternate Direction Method of Multipliers. The study of the ergodic and non ergodic convergence rates show similar rates with the classical Douglas-Rachford splitting scheme. We end with an application to a multi-block convex optimization model which leads to a generalized Separable Augmented Lagrangian Algorithm.