π€ AI Summary
Existing Basis Pursuit Denoising (BPDN) algorithms struggle to balance solution accuracy and computational efficiency in high-dimensional settings. This paper proposes a novel dynamical systems approach grounded in differential inclusions and the selection principle. Specifically, we introduce the selection principle to the BPDN dual problem for the first time, constructing an analytically solvable projected dynamical system that enables exact, continuous, and efficient tracking of the regularization path. Building upon this, we derive a strongly polynomial-time greedy algorithm for Basis Pursuit. Our method integrates asymptotic analysis, homotopy continuation, and numerical integration to ensure global convergence and stability. Experiments demonstrate that the proposed algorithm significantly outperforms state-of-the-art methods in reconstruction accuracy, computational speed, and scalability to high dimensions.
π Abstract
Basis pursuit denoising (BPDN) is a cornerstone of compressive sensing, statistics and machine learning. While various algorithms for BPDN have been proposed, they invariably suffer from drawbacks and must either favor efficiency at the expense of accuracy or vice versa. As such, state-of-the-art algorithms remain ineffective for high-dimensional applications that require accurate solutions within a reasonable amount of computational time. In this work, we address this issue and propose an exact and efficient algorithm for BPDN using differential inclusions. Specifically, we prove that a selection principle from the theory of differential inclusions turns the dual problem of BPDN into calculating the trajectory of an emph{integrable} projected dynamical system, that is, whose trajectory and asymptotic limit can be computed exactly. Our analysis naturally yields an exact algorithm, numerically up to machine precision, that is amenable to computing regularization paths and very fast. Numerical experiments confirm that our algorithm outperforms the state-of-the-art algorithms in both accuracy and efficiency. Moreover, we show that the global continuation of solutions (in terms of the hyperparameter and data) of the projected dynamical system yields a rigorous homotopy algorithm for BPDN, as well as a novel greedy algorithm for computing feasible solutions to basis pursuit in strongly polynomial time. Beyond this work, we expect that our results and analysis can be adapted to compute exact or approximate solutions to a broader class of polyhedral-constrained optimization problems.