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arXiv · 2507.07428

Relocated Fixed-Point Iterations with Applications to Variable Stepsize Resolvent Splitting

Felipe Atenas·Heinz H. Bauschke·Minh N. Dao·Matthew K. Tam
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Abstract

In this work, we develop a convergence framework for iterative algorithms whose updates can be described by a one-parameter family of nonexpansive operators. Within the framework, each step involving one of the main algorithmic operators is followed by a second step which ''relocates'' fixed points of the current operator to the next. As a consequence, our analysis does not require the family of nonexpansive operators to have a common fixed point, as frequently assumed in the literature. Our analysis uses a parametric extension of the demiclosedness principle for nonexpansive operators. As an application of our convergence results, we develop a version of the graph-based extension of the Douglas--Rachford algorithm for finding a zero of the sum of $N\geq 2$ maximally monotone operators, which does not require the resolvent parameter to be constant across iterations.

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Felipe Atenas, Heinz H. Bauschke, Minh N. Dao, Matthew K. Tam. 2025-07-10. Relocated Fixed-Point Iterations with Applications to Variable Stepsize Resolvent Splitting. https://arxiv.org/abs/2507.07428

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