Special Lecture - 2/08, 12:00PM, Duncan Hall 1049

Dr. Andreas Kloeckner

Courant Institute of Mathematical Sciences
New York University

"Quadrature by Expansion: A New Method for the Evaluation of Layer Potentials"

Integral equation methods for the solution of partial differential equations, when coupled with suitable fast algorithms, yield geometrically flexible, asymptotically optimal and well-conditioned schemes in either interior or exterior domains. The practical application of these methods, however, requires the accurate evaluation of boundary integrals with singular, weakly singular or nearly singular kernels. I will be presenting a new systematic, high-order approach that works for any singularity (including hypersingular kernels), based only on the assumption that the field induced by the integral operator is locally smooth when restricted to either the interior or the exterior. Discontinuities in the field across the boundary are permitted. The scheme, denoted QBX (quadrature by expansion), is easy to implement and compatible with fast hierarchical algorithms such as the fast multipole method. I will also present accuracy tests for a variety of integral operators in two dimensions on smooth and corner domains. (with L. Greengard, A. Barnett, M. O'Neil).