A Two Stepsize SQP Method for Nonlinear Equality Constrained Stochastic Optimization

Fuente: arXiv
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Autor principal: O'Neill, Michael J.
Formato: Preprint
Publicado: 2024
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author O'Neill, Michael J.
author_facet O'Neill, Michael J.
contents We develop a Sequential Quadratic Optimization (SQP) algorithm for minimizing a stochastic objective function subject to deterministic equality constraints. The method utilizes two different stepsizes, one which exclusively scales the component of the step corrupted by the variance of the stochastic gradient estimates and a second which scales the entire step. We prove that this stepsize splitting scheme has a worst-case complexity result which improves over the best known result for this class of problems. In terms of approximately satisfying the constraint violation, this complexity result matches that of deterministic SQP methods, up to constant factors, while matching the known optimal rate for stochastic SQP methods to approximately minimize the norm of the gradient of the Lagrangian. We also propose and analyze multiple variants of our algorithm. One of these variants is based upon popular adaptive gradient methods for unconstrained stochastic optimization while another incorporates a safeguarded line search along the constraint violation. Preliminary numerical experiments show competitive performance against state of the art algorithms. In addition, in these experiments, we observe an improved rate of convergence in terms of the constraint violation, as predicted by the theoretical results.
format Preprint
id arxiv_https___arxiv_org_abs_2408_16656
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Two Stepsize SQP Method for Nonlinear Equality Constrained Stochastic Optimization
O'Neill, Michael J.
Optimization and Control
49M37, 65K05, 65K10, 90C15, 90C30, 90C55
We develop a Sequential Quadratic Optimization (SQP) algorithm for minimizing a stochastic objective function subject to deterministic equality constraints. The method utilizes two different stepsizes, one which exclusively scales the component of the step corrupted by the variance of the stochastic gradient estimates and a second which scales the entire step. We prove that this stepsize splitting scheme has a worst-case complexity result which improves over the best known result for this class of problems. In terms of approximately satisfying the constraint violation, this complexity result matches that of deterministic SQP methods, up to constant factors, while matching the known optimal rate for stochastic SQP methods to approximately minimize the norm of the gradient of the Lagrangian. We also propose and analyze multiple variants of our algorithm. One of these variants is based upon popular adaptive gradient methods for unconstrained stochastic optimization while another incorporates a safeguarded line search along the constraint violation. Preliminary numerical experiments show competitive performance against state of the art algorithms. In addition, in these experiments, we observe an improved rate of convergence in terms of the constraint violation, as predicted by the theoretical results.
title A Two Stepsize SQP Method for Nonlinear Equality Constrained Stochastic Optimization
topic Optimization and Control
49M37, 65K05, 65K10, 90C15, 90C30, 90C55
url https://arxiv.org/abs/2408.16656