Abstract
Algorithms of quotient-difference type for computing singular values have recently attracted revived interest. In particular, the dqds algorithm, being numerically stable, is now recognized as an effective method in practice, where an appropriate setting of the shifts is indispensable for accelerating the convergence. In this report we propose a simple shift strategy that is theoretically guaranteed to render asymptotic superquadratic convergence. We also present a numerical example demonstrating the superquadratic convergence.
