On Error Growth Functions of Runge-Kutta Methods
E. Hairer and M. Zennaro
Abstract. This paper studies estimates of the form $\| y_1 -\widehat y_1 \| \le \varphi (h\nu )\|y_0-\widehat y_0\|$, where $y_1,\widehat y_1$ are the numerical solutions of a Runge-Kutta method applied to a stiff differential equation satisfying a one-sided Lipschitz condition (with constant $\nu$). An explicit formula for the optimal function $\varphi (x)$ is given, and it is shown to be superexponential, i.e., $\varphi (x_1) \varphi (x_2) \le \varphi (x_1+x_2)$ if $x_1$ and $x_2$ have the same sign. As a consequence, results on asymptotic stability are obtained. Furthermore, upper bounds for $\varphi (x)$ are presented that can be easily computed from the coefficients of the method.
Key Words. Runge-Kutta methods, error growth functions, stiff differential equations, B-stability, asymptotic stability, superexponential functions.