Researchers have developed a new class of preconditioned iterative methods for solving linear systems, resulting in faster runtimes for various linear algebraic problems.
The methods involve constructing a low-rank Nyström approximation to the matrix using sparse random matrix sketching.
The approximation is then used to create a preconditioner, which is inverted quickly using additional levels of random sketching and preconditioning.
The research proves the convergence of the methods is dependent on the average condition number of the matrix, which improves as the rank of the Nyström approximation increases.