Andres Contreras – Optimization Online

Convergence Results for Primal-Dual Algorithms in the Presence of Adjoint Mismatch

Published: 2022/04/17

Convex Optimization, Nonsmooth Optimization adjoint mismatch, convergence analysis, convex optimization, CT reconstruction, fixed point theory, forward-backward splitting, primal-dual algorithms, Tseng’s splitting

Most optimization problems arising in imaging science involve high-dimensional linear operators and their adjoints. In the implementations of these operators, approximations may be introduced for various practical considerations (e.g., memory limitation, computational cost, convergence speed), leading to an adjoint mismatch. This occurs for the X-ray tomographic inverse problems found in Computed Tomography (CT), where the … Read more

Proximal splitting algorithms: Relax them all!

Published: 2020/01/10

Nonlinear Optimization, Nonsmooth Optimization

Convex optimization problems, whose solutions live in very high dimensional spaces, have become ubiquitous. To solve them, proximal splitting algorithms are particularly adequate: they consist of simple operations, by handling the terms in the objective function separately. We present several existing proximal splitting algorithms and we derive new ones, within a unified framework, which consists … Read more