Verification of First-Order Methods for Parametric Quadratic Optimization

Fuente: arXiv
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Autori principali: Ranjan, Vinit, Stellato, Bartolomeo
Natura: Preprint
Pubblicazione: 2024
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author Ranjan, Vinit
Stellato, Bartolomeo
author_facet Ranjan, Vinit
Stellato, Bartolomeo
contents We introduce a numerical framework to verify the finite step convergence of first-order methods for parametric convex quadratic optimization. We formulate the verification problem as a mathematical optimization problem where we maximize a performance metric (e.g., fixed-point residual at the last iteration) subject to constraints representing proximal algorithm steps (e.g., linear system solutions, projections, or gradient steps). Our framework is highly modular because we encode a wide range of proximal algorithms as variations of two primitive steps: affine steps and element-wise maximum steps. Compared to standard convergence analysis and performance estimation techniques, we can explicitly quantify the effects of warm-starting by directly representing the sets where the initial iterates and parameters live. We show that the verification problem is NP-hard, and we construct strong semidefinite programming relaxations using various constraint tightening techniques. Numerical examples in nonnegative least squares, network utility maximization, Lasso, and optimal control show a significant reduction in pessimism of our framework compared to standard worst-case convergence analysis techniques.
format Preprint
id arxiv_https___arxiv_org_abs_2403_03331
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Verification of First-Order Methods for Parametric Quadratic Optimization
Ranjan, Vinit
Stellato, Bartolomeo
Optimization and Control
We introduce a numerical framework to verify the finite step convergence of first-order methods for parametric convex quadratic optimization. We formulate the verification problem as a mathematical optimization problem where we maximize a performance metric (e.g., fixed-point residual at the last iteration) subject to constraints representing proximal algorithm steps (e.g., linear system solutions, projections, or gradient steps). Our framework is highly modular because we encode a wide range of proximal algorithms as variations of two primitive steps: affine steps and element-wise maximum steps. Compared to standard convergence analysis and performance estimation techniques, we can explicitly quantify the effects of warm-starting by directly representing the sets where the initial iterates and parameters live. We show that the verification problem is NP-hard, and we construct strong semidefinite programming relaxations using various constraint tightening techniques. Numerical examples in nonnegative least squares, network utility maximization, Lasso, and optimal control show a significant reduction in pessimism of our framework compared to standard worst-case convergence analysis techniques.
title Verification of First-Order Methods for Parametric Quadratic Optimization
topic Optimization and Control
url https://arxiv.org/abs/2403.03331