🤖 AI Summary
This work proposes an Orthogonal Approximate Message Passing (OAMP) algorithm for signal estimation in rectangular spiked matrix models corrupted by general rotationally invariant noise. The method establishes a flexible OAMP framework applicable to arbitrary rotationally invariant noise distributions, derives an optimal variant that minimizes the mean squared error at each iteration, and develops a rigorous state evolution theory to precisely characterize its high-dimensional dynamics. In the special case of Gaussian noise, the fixed points of the proposed algorithm coincide with those of standard AMP. Under more general rotationally invariant noise, the algorithm achieves Bayes-optimal performance under certain conditions, demonstrating its potential for statistical optimality.
📝 Abstract
We propose an orthogonal approximate message passing (OAMP) algorithm for signal estimation in the rectangular spiked matrix model with general rotationally invariant (RI) noise. We establish a rigorous state evolution that exactly characterizes the high-dimensional dynamics of the algorithm. Building on this framework, we derive an optimal variant of OAMP that minimizes the predicted mean-squared error at each iteration. For the special case of i.i.d. Gaussian noise, the fixed point of the proposed OAMP algorithm coincides with that of the standard AMP algorithm. For general RI noise models, we conjecture that the optimal OAMP algorithm is statistically optimal within a broad class of iterative methods, and achieves Bayes-optimal performance in certain regimes.