“…The classic simple subspace, or simultaneous, iteration method, extends the idea of the power method which computes the largest eigenvalue and its eigenvector (see [16,17,24,26] for example), performing repeated matrix multiplication followed by orthogonalization. More elaborative algorithms including Arnoldi methods [14,13], Lanczos methods [21,12], Jacobi-Davidson methods [23,2], to cite a few for each type, are specifically designed for large-scale but sparse matrices or other types of structured matrices.…”