Quasi-Self-Concordant Optimization with Lewis Weights

Fuente: arXiv
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Main Authors: Ene, Alina, Nguyen, Ta Duy, Vladu, Adrian
Format: Preprint
Published: 2025
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author Ene, Alina
Nguyen, Ta Duy
Vladu, Adrian
author_facet Ene, Alina
Nguyen, Ta Duy
Vladu, Adrian
contents In this paper, we study the problem $\min_{x\in \mathbb{R}^{d},Nx=v}\sum_{i=1}^{n}f((Ax-b)_{i})$ for a quasi-self-concordant function $f:\mathbb{R}\to\mathbb{R}$, where $A,N$ are $n\times d$ and $m\times d$ matrices, $b,v$ are vectors of length $n$ and $m$ with $n\ge d.$ We show an algorithm based on a trust-region method with an oracle that can be implemented using $\widetilde{O}(d^{1/3})$ linear system solves, improving the $\widetilde{O}(n^{1/3})$ oracle by {[}Adil-Bullins-Sachdeva, NeurIPS 2021{]}. Our implementation of the oracle relies on solving the overdetermined $\ell_{\infty}$-regression problem $\min_{x\in\mathbb{R}^{d},Nx=v}\|Ax-b\|_{\infty}$. We provide an algorithm that finds a $(1+ε)$-approximate solution to this problem using $O((d^{1/3}/ε+1/ε^{2})\log(n/ε))$ linear system solves. This algorithm leverages $\ell_{\infty}$ Lewis weight overestimates and achieves this iteration complexity via a simple lightweight IRLS approach, inspired by the work of {[}Ene-Vladu, ICML 2019{]}. Experimentally, we demonstrate that our algorithm significantly improves the runtime of the standard CVX solver.
format Preprint
id arxiv_https___arxiv_org_abs_2510_22088
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quasi-Self-Concordant Optimization with Lewis Weights
Ene, Alina
Nguyen, Ta Duy
Vladu, Adrian
Optimization and Control
Data Structures and Algorithms
In this paper, we study the problem $\min_{x\in \mathbb{R}^{d},Nx=v}\sum_{i=1}^{n}f((Ax-b)_{i})$ for a quasi-self-concordant function $f:\mathbb{R}\to\mathbb{R}$, where $A,N$ are $n\times d$ and $m\times d$ matrices, $b,v$ are vectors of length $n$ and $m$ with $n\ge d.$ We show an algorithm based on a trust-region method with an oracle that can be implemented using $\widetilde{O}(d^{1/3})$ linear system solves, improving the $\widetilde{O}(n^{1/3})$ oracle by {[}Adil-Bullins-Sachdeva, NeurIPS 2021{]}. Our implementation of the oracle relies on solving the overdetermined $\ell_{\infty}$-regression problem $\min_{x\in\mathbb{R}^{d},Nx=v}\|Ax-b\|_{\infty}$. We provide an algorithm that finds a $(1+ε)$-approximate solution to this problem using $O((d^{1/3}/ε+1/ε^{2})\log(n/ε))$ linear system solves. This algorithm leverages $\ell_{\infty}$ Lewis weight overestimates and achieves this iteration complexity via a simple lightweight IRLS approach, inspired by the work of {[}Ene-Vladu, ICML 2019{]}. Experimentally, we demonstrate that our algorithm significantly improves the runtime of the standard CVX solver.
title Quasi-Self-Concordant Optimization with Lewis Weights
topic Optimization and Control
Data Structures and Algorithms
url https://arxiv.org/abs/2510.22088