Improvement of the accuracy of the approximate solution of the Block BiCR method

Abstract

Block Krylov subspace methods are efficient solvers for linear systems with multiple right-hand sides in terms of the number of iterations and computational time. As one of Block Krylov subspace methods, the Block BiCR method has been proposed by Zhang et al. in 2013. This method often shows a smooth convergence behavior compared with the Block BiCG method. However, the accuracy of the approximate solution generated by the Block BiCR method often deteriorates. In this paper we propose a modified Block BiCR method in order to improve the accuracy of the approximate solutions.