Distributed Riemannian Optimization in Geodesically Non-convex Environments

Fuente: arXiv
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Auteurs principaux: Wang, Xiuheng, Borsoi, Ricardo, Richard, Cédric, Sayed, Ali H.
Format: Preprint
Publié: 2025
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author Wang, Xiuheng
Borsoi, Ricardo
Richard, Cédric
Sayed, Ali H.
author_facet Wang, Xiuheng
Borsoi, Ricardo
Richard, Cédric
Sayed, Ali H.
contents This paper studies the problem of distributed Riemannian optimization over a network of agents whose cost functions are geodesically smooth but possibly geodesically non-convex. Extending a well-known distributed optimization strategy called diffusion adaptation to Riemannian manifolds, we show that the resulting algorithm, the Riemannian diffusion adaptation, provably exhibits several desirable behaviors when minimizing a sum of geodesically smooth non-convex functions over manifolds of bounded curvature. More specifically, we establish that the algorithm can approximately achieve network agreement in the sense that Fréchet variance of the iterates among the agents is small. Moreover, the algorithm is guaranteed to converge to a first-order stationary point for general geodesically non-convex cost functions. When the global cost function additionally satisfies the local Riemannian Polyak-Lojasiewicz (PL) condition, we also show that it converges linearly under a constant step size up to a steady-state error. Finally, we apply this algorithm to a decentralized robust principal component analysis (PCA) problem formulated on the Grassmann manifold and low-rank matrix completion problems and illustrate its convergence and performance through numerical simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2512_04915
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Distributed Riemannian Optimization in Geodesically Non-convex Environments
Wang, Xiuheng
Borsoi, Ricardo
Richard, Cédric
Sayed, Ali H.
Signal Processing
This paper studies the problem of distributed Riemannian optimization over a network of agents whose cost functions are geodesically smooth but possibly geodesically non-convex. Extending a well-known distributed optimization strategy called diffusion adaptation to Riemannian manifolds, we show that the resulting algorithm, the Riemannian diffusion adaptation, provably exhibits several desirable behaviors when minimizing a sum of geodesically smooth non-convex functions over manifolds of bounded curvature. More specifically, we establish that the algorithm can approximately achieve network agreement in the sense that Fréchet variance of the iterates among the agents is small. Moreover, the algorithm is guaranteed to converge to a first-order stationary point for general geodesically non-convex cost functions. When the global cost function additionally satisfies the local Riemannian Polyak-Lojasiewicz (PL) condition, we also show that it converges linearly under a constant step size up to a steady-state error. Finally, we apply this algorithm to a decentralized robust principal component analysis (PCA) problem formulated on the Grassmann manifold and low-rank matrix completion problems and illustrate its convergence and performance through numerical simulations.
title Distributed Riemannian Optimization in Geodesically Non-convex Environments
topic Signal Processing
url https://arxiv.org/abs/2512.04915