Norges Teknisk-naturvitenskapelige Universitet Expint — a Matlab 1 Package for Exponential Integrators

Recently, a great deal of attention has been focused on the construction of exponential integrators for semi-linear problems. In this paper we describe a matlab package which aims to facilitate the quick deployment and testing of exponential integrators, of Runge–Kutta, multistep and general linear type. A large number of integrators are included in this package along with several well known examples. The so-called φ-functions and their evaluation is crucial for stability and speed of exponential integrators, and the approach taken here is through a modification of the scaling and squaring technique; the most common approach used for computing the matrix exponential.