Convergence and Complexity Guarantee for Inexact First-order Riemannian Optimization Algorithms

Fuente: arXiv
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Autores principales: Li, Yuchen, Balzano, Laura, Needell, Deanna, Lyu, Hanbaek
Formato: Preprint
Publicado: 2024
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author Li, Yuchen
Balzano, Laura
Needell, Deanna
Lyu, Hanbaek
author_facet Li, Yuchen
Balzano, Laura
Needell, Deanna
Lyu, Hanbaek
contents We analyze inexact Riemannian gradient descent (RGD) where Riemannian gradients and retractions are inexactly (and cheaply) computed. Our focus is on understanding when inexact RGD converges and what is the complexity in the general nonconvex and constrained setting. We answer these questions in a general framework of tangential Block Majorization-Minimization (tBMM). We establish that tBMM converges to an $ε$-stationary point within $O(ε^{-2})$ iterations. Under a mild assumption, the results still hold when the subproblem is solved inexactly in each iteration provided the total optimality gap is bounded. Our general analysis applies to a wide range of classical algorithms with Riemannian constraints including inexact RGD and proximal gradient method on Stiefel manifolds. We numerically validate that tBMM shows improved performance over existing methods when applied to various problems, including nonnegative tensor decomposition with Riemannian constraints, regularized nonnegative matrix factorization, and low-rank matrix recovery problems.
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id arxiv_https___arxiv_org_abs_2405_03073
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Convergence and Complexity Guarantee for Inexact First-order Riemannian Optimization Algorithms
Li, Yuchen
Balzano, Laura
Needell, Deanna
Lyu, Hanbaek
Optimization and Control
Machine Learning
We analyze inexact Riemannian gradient descent (RGD) where Riemannian gradients and retractions are inexactly (and cheaply) computed. Our focus is on understanding when inexact RGD converges and what is the complexity in the general nonconvex and constrained setting. We answer these questions in a general framework of tangential Block Majorization-Minimization (tBMM). We establish that tBMM converges to an $ε$-stationary point within $O(ε^{-2})$ iterations. Under a mild assumption, the results still hold when the subproblem is solved inexactly in each iteration provided the total optimality gap is bounded. Our general analysis applies to a wide range of classical algorithms with Riemannian constraints including inexact RGD and proximal gradient method on Stiefel manifolds. We numerically validate that tBMM shows improved performance over existing methods when applied to various problems, including nonnegative tensor decomposition with Riemannian constraints, regularized nonnegative matrix factorization, and low-rank matrix recovery problems.
title Convergence and Complexity Guarantee for Inexact First-order Riemannian Optimization Algorithms
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2405.03073