Efficient Parallel Computation of the Stochastic MV-PURE Estimator by the Hybrid Steepest Descent Method

In this paper we consider the problem of efficient computation of the stochastic MV-PURE estimator which is a reduced-rank estimator designed for robust linear estimation in ill-conditioned inverse problems. Our motivation for this result stems from the fact that the reduced-rank estimation by the stochastic MV-PURE estimator, while avoiding the problem of regularization parameter selection appearing in a common regularization technique used in inverse problems and machine learning, presents computational challenge due to nonconvexity induced by the rank constraint. To combat this problem, we propose a recursive scheme for computation of the general form of the stochastic MV-PURE estimator which does not require any matrix inversion and utilize the inherently parallel hybrid steepest descent method. We verify efficiency of the proposed scheme in numerical simulations.