A block EN algorithm for nonsymmetric linear systems with multiple right-hand sides

The EN method proposed by Eirola and Nevanlinna is extended to a block vers ion for solving nonsymmetric linear systems with multiple right-hand sides. Some basic properties of the block-EN method are shown. We use the deflati on technique in the block-EN method to delete linearly dependent vectors in the underlying block sequences and drop the corresponding linear systems o r converged linear systems. However, our BEN method with deflation procedur e still keeps the blockwise computation, instead of vectorwise generation o f the basis vectors for the underlying block subspace. Numerical experiment s show that the algorithm is efficient and robust. (C) 1999 Elsevier Scienc e Inc. All rights reserved.