Generalized Composed Alternating Relaxed Projection Algorithm for Two-Set Feasibility Problem

Fuente: arXiv
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Main Authors: Li, Xinxin, Wei, Yudong, Zhang, Hao
Format: Preprint
Published: 2026
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author Li, Xinxin
Wei, Yudong
Zhang, Hao
author_facet Li, Xinxin
Wei, Yudong
Zhang, Hao
contents We study the two-set feasibility problem of finding a point in the intersection $X\cap Y$ of closed convex sets in a Hilbert space. We propose a generalized composed alternating relaxed projection algorithm (gCARPA) that blends Douglas-Rachford-type and projection-reflection-type dynamics via an outer averaging step $μ$ and an internal relaxation $(γ,θ,η)$. The algorithm contains several classical projection methods as special cases. We also introduce its non-stationary variant, in which $(γ_k,θ_k,η_k)$ vary over iterations, and establish its convergence. For the subspace feasibility model, we derive an explicit spectral characterization via principal-angle block decompositions, yielding computable subdominant-eigenvalue factors and a minimax parameter-selection recipe in a symmetric regime that targets critical damping on principal-angle planes. Numerical experiments illustrate that the generalized relaxation and its non-stationary tuning can improve or match baseline methods in problem-dependent regimes.
format Preprint
id arxiv_https___arxiv_org_abs_2604_17276
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Generalized Composed Alternating Relaxed Projection Algorithm for Two-Set Feasibility Problem
Li, Xinxin
Wei, Yudong
Zhang, Hao
Optimization and Control
Numerical Analysis
We study the two-set feasibility problem of finding a point in the intersection $X\cap Y$ of closed convex sets in a Hilbert space. We propose a generalized composed alternating relaxed projection algorithm (gCARPA) that blends Douglas-Rachford-type and projection-reflection-type dynamics via an outer averaging step $μ$ and an internal relaxation $(γ,θ,η)$. The algorithm contains several classical projection methods as special cases. We also introduce its non-stationary variant, in which $(γ_k,θ_k,η_k)$ vary over iterations, and establish its convergence. For the subspace feasibility model, we derive an explicit spectral characterization via principal-angle block decompositions, yielding computable subdominant-eigenvalue factors and a minimax parameter-selection recipe in a symmetric regime that targets critical damping on principal-angle planes. Numerical experiments illustrate that the generalized relaxation and its non-stationary tuning can improve or match baseline methods in problem-dependent regimes.
title Generalized Composed Alternating Relaxed Projection Algorithm for Two-Set Feasibility Problem
topic Optimization and Control
Numerical Analysis
url https://arxiv.org/abs/2604.17276