Fast Alternating Direction Methods for Optimization
Tom Goldstein
Post-Doctoral Fellow at the Rice University Department of Electrical Engineering
Abstract:
Alternating direction methods are a commonplace tool for general
mathematical programming and optimization. These methods have become
particularly important in the field of variational image processing, which
frequently requires the minimization of non-differentiable objectives. This
paper considers accelerated (i.e. fast) variants of two common alternating
direction methods: the Alternating Direction Method of Multipliers (ADMM) and
the Alternating Minimization Algorithm (AMA). The proposed acceleration is of
the form first proposed by Nesterov for gradient descent methods. In the case
that the objective function is strongly convex, global convergence bounds are
provided for both classical and accelerated variants of the methods.
Numerical examples are presented to demonstrating the superior performance of
the fast methods.