TW 536

Andreas Asheim and Daan Huybrechs
Asymptotic analysis of numerical steepest descent with path approximations

Abstract

We propose a variant of the numerical method of steepest descent for oscillatory integrals by using a low-cost explicit polynomial approximation of the paths of steepest descent. A loss of asymptotic order is observed, but in the most relevant cases the overall asymptotic order remains higher than a truncated asymptotic expansion at similar computational effort. Theoretical results based on number theory underpinning the mechanisms behind this effect are presented.

report.pdf (277K) / mailto: D. Huybrechs