Using the RD rational Arnoldi method for exponential integrators

In this paper we investigate some practical aspects concerning the use of the Restricted-Denominator (RD) rational Arnoldi method for the computation of the core functions of exponential integrators for parabolic problems. We derive some useful a-posteriori bounds together with some hints for a suitable implementation inside the integrators. Numerical ex- periments arising from the discretization of sectorial operators are pre- sented.