Stochastic and incremental subgradient methods for convex optimization on Hadamard spaces

Fuente: arXiv
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Auteurs principaux: Goodwin, Ariel, Lewis, Adrian S., López-Acedo, Genaro, Nicolae, Adriana
Format: Preprint
Publié: 2024
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author Goodwin, Ariel
Lewis, Adrian S.
López-Acedo, Genaro
Nicolae, Adriana
author_facet Goodwin, Ariel
Lewis, Adrian S.
López-Acedo, Genaro
Nicolae, Adriana
contents As a foundation for optimization, convexity is useful beyond the classical settings of Euclidean and Hilbert space. The broader arena of nonpositively curved metric spaces, which includes manifolds like hyperbolic space, as well as metric trees and more general CAT(0) cubical complexes, supports primal tools like proximal operations for geodesically convex functions. However, the lack of linear structure in such spaces complicates dual constructions like subgradients. To address this hurdle, we introduce a new type of subgradient for functions on Hadamard spaces, based on Busemann functions. Our notion supports generalizations of classical stochastic and incremental subgradient methods, with guaranteed complexity bounds. We illustrate with subgradient algorithms for $p$-mean problems in general Hadamard spaces, in particular computing medians in BHV tree space.
format Preprint
id arxiv_https___arxiv_org_abs_2412_06730
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Stochastic and incremental subgradient methods for convex optimization on Hadamard spaces
Goodwin, Ariel
Lewis, Adrian S.
López-Acedo, Genaro
Nicolae, Adriana
Optimization and Control
Computational Geometry
Data Structures and Algorithms
Numerical Analysis
90C48, 65Y20, 49M29
G.1.6
As a foundation for optimization, convexity is useful beyond the classical settings of Euclidean and Hilbert space. The broader arena of nonpositively curved metric spaces, which includes manifolds like hyperbolic space, as well as metric trees and more general CAT(0) cubical complexes, supports primal tools like proximal operations for geodesically convex functions. However, the lack of linear structure in such spaces complicates dual constructions like subgradients. To address this hurdle, we introduce a new type of subgradient for functions on Hadamard spaces, based on Busemann functions. Our notion supports generalizations of classical stochastic and incremental subgradient methods, with guaranteed complexity bounds. We illustrate with subgradient algorithms for $p$-mean problems in general Hadamard spaces, in particular computing medians in BHV tree space.
title Stochastic and incremental subgradient methods for convex optimization on Hadamard spaces
topic Optimization and Control
Computational Geometry
Data Structures and Algorithms
Numerical Analysis
90C48, 65Y20, 49M29
G.1.6
url https://arxiv.org/abs/2412.06730