A Safeguarded Projected-Gradient Framework for Complementarity Constrained Least Squares Problems
Abstract
Both generalized absolute value equations (GAVEs) and linear complementarity problems (LCPs) can be formulated as least-squares problems over the complementarity set. Because this feasible set is nonconvex, projected stationarity does not in general imply zero residual. We develop a safeguarded projected-gradient framework with a linear-system refinement on a selected polyhedral face. We establish matrix conditions under which every projected stationary point is a global solution and derive corresponding global convergence results. Specifically, when refinement on a correct active face returns a solution, we give explicit iteration bounds for active-face identification and prove finite termination. Numerical experiments on GAVE and LCP benchmarks demonstrate the high accuracy of the proposed framework across the tested settings.
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BibTeX
@misc{xiao2026safeguarded,
title = {{A Safeguarded Projected-Gradient Framework for Complementarity Constrained Least Squares Problems}},
author = {Lianghai Xiao and Wei Zhang and Jiayi Zhong},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.20786},
eprint = {2607.20786},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.20786},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Safeguarded Projected-Gradient Framework for Complementarity Constrained Least Squares Problems
AU - Lianghai Xiao
AU - Wei Zhang
AU - Jiayi Zhong
PY - 2026
DA - 2026/09/02
PB - arXiv
DO - 10.48550/arxiv.2607.20786
UR - https://arxiv.org/abs/2607.20786
AB - Both generalized absolute value equations (GAVEs) and linear complementarity problems (LCPs) can be formulated as least-squares problems over the complementarity set. Because this feasible set is nonconvex, projected stationarity does not in general imply zero residual. We develop a safeguarded projected-gradient framework with a linear-system refinement on a selected polyhedral face. We establish matrix conditions under which every projected stationary point is a global solution and derive corresponding global convergence results. Specifically, when refinement on a correct active face returns a solution, we give explicit iteration bounds for active-face identification and prove finite termination. Numerical experiments on GAVE and LCP benchmarks demonstrate the high accuracy of the proposed framework across the tested settings.
ER -