First-Order Sparse Convex Optimization: Better Rates with Sparse Updates

Fuente: arXiv
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Main Author: Garber, Dan
Format: Preprint
Published: 2025
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author Garber, Dan
author_facet Garber, Dan
contents It was recently established that for convex optimization problems with sparse optimal solutions (be it entry-wise sparsity or matrix rank-wise sparsity) it is possible to design first-order methods with linear convergence rates that depend on an improved mixed-norm condition number of the form $\frac{β_1{}s}{α_2}$, where $β_1$ is the $\ell_1$-Lipschitz continuity constant of the gradient, $α_2$ is the $\ell_2$-quadratic growth constant, and $s$ is the sparsity of optimal solutions. However, beyond the improved convergence rate, these methods are unable to leverage the sparsity of optimal solutions towards improving the runtime of each iteration as well, which may still be prohibitively high for high-dimensional problems. In this work, we establish that linear convergence rates which depend on this improved condition number can be obtained using only sparse updates, which may result in overall significantly improved running times. Moreover, our methods are considerably easier to implement.
format Preprint
id arxiv_https___arxiv_org_abs_2506_19075
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle First-Order Sparse Convex Optimization: Better Rates with Sparse Updates
Garber, Dan
Optimization and Control
Machine Learning
It was recently established that for convex optimization problems with sparse optimal solutions (be it entry-wise sparsity or matrix rank-wise sparsity) it is possible to design first-order methods with linear convergence rates that depend on an improved mixed-norm condition number of the form $\frac{β_1{}s}{α_2}$, where $β_1$ is the $\ell_1$-Lipschitz continuity constant of the gradient, $α_2$ is the $\ell_2$-quadratic growth constant, and $s$ is the sparsity of optimal solutions. However, beyond the improved convergence rate, these methods are unable to leverage the sparsity of optimal solutions towards improving the runtime of each iteration as well, which may still be prohibitively high for high-dimensional problems. In this work, we establish that linear convergence rates which depend on this improved condition number can be obtained using only sparse updates, which may result in overall significantly improved running times. Moreover, our methods are considerably easier to implement.
title First-Order Sparse Convex Optimization: Better Rates with Sparse Updates
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2506.19075