September 28, 2018 - 3:00pm

**Speaker**: Nicholas Knight (UC Merced, Applied Mathematics)

**Title**: Butterflies in Layered Media

**Abstract**: Using a combination of physical-domain and Fourier-domain integral representations, we present an iterative algorithm for solving the two-dimensional Helmholtz equation in layered media geometries. The scheme is accelerated by use of a butterfly algorithm, which allows for nearly optimal $O(N \log^2 N)$ asymptotic scaling in the high-frequency limit.

### Location

COB1 265