# Publications

## 2014

L. Greengard, T. Hagstrom and S. Jiang,
* The solution of the scalar wave equation in the exterior of a sphere, *
J. Comput. Phys., 274, 191-207 (2014).
A. J. Ilotta, S. Chandrashekar, A. Kloeckner, H. J. Chang, N. M. Trease,
C. P. Grey, L. Greengard, A. Jerschow,
* Visualizing skin effects in conductors with MRI: 7-Li MRI experiments
and calculations, *
J. Magnetic Resonance, 245, 143-149 (2014).
J. Lai, M. Kobayashi, and L. Greengard,
* A fast solver for multi-particle scattering in a layered medium, *
Optics Express, 22, 20481–20499 (2014).
L. Greengard, K. L. Ho and J.-Y. Lee,
* A fast direct solver for scattering from periodic structures with
multiple material interfaces in two dimensions, *
J. Comput. Phys., 258, 738-751 (2014).
L. Greengard, M. O'Neil, and A. Pataki,
* On the efficient representation of the half-space impedance
Green's function for the Helmholtz equation, *
Wave Motion, 51, 1-13 (2014).
K. L. Ho and L. Greengard,
* A fast direct least squares algorithm for hierarchically structured
block separable matrices, *
J. Comput. Phys., 258, 738-751 (2014).
F. Vico, L. Greengard, and Z. Gimbutas,
* Boundary integral equation analysis on the sphere, *
Numer. Math., to appear.
S. Jiang and L. Greengard and S. Wang,
* Efficient sum-of-exponentials approximations for the
heat kernel and their applications, *
Adv. Comput. Math., to appear.
T. Askham and L. Greengard,
* Norm-preserving discretization of integral equations for elliptic PDEs
with internal layers I: the one-dimensional case, *
SIAM Review, to appear.
S. Jiang, L. Greengard, and W. Bao,
* Fast and accurate evaluation of nonlocal Coulomb and dipole-dipole interactions
via the nonuniform FFT, *
SIAM J. Sci. Comput., to appear.
C. Epstein, L. Greengard and M. O'Neil,
* Debye sources, Beltrami fields and a complex
structure on Maxwell fields, *
Comm. Pure Appl. Math., to appear.
J. Lai, S. Ambikasaran, and L. Greengard,
* A fast direct solver for high frequency scattering from a
large cavity in two dimensions, *
arXiv:1404.3451, SIAM J. Sci. Comput., to appear.
J.Sifuentes, Z. Gimbutas, and L. Greengard,
* Randomized methods for rank-deficient linear systems, *
arXiv:1401.3068, submitted.
S. Ambikasaran, D. Foreman-Mackey, L. Greengard,
D. W. Hogg, and M. O’Neil,
* Fast direct methods for Gaussian processes
and the analysis of NASA Kepler mission data, *
arXiv:1403.6015, submitted.
Z. Gimbutas and L. Greengard,
* A fast multipole method for the evaluation of elastostatic fields in a
half-space with zero normal stress, *
arXiv:1404.0036, submitted.
F. Vico, L. Greengard, Z. Gimbutas, and M. Ferrando,
* The decoupled potential integral equation for time-harmonic
electromagnetic scattering, *
arXiv:1404.0749, submitted.
C. Borges and L. Greengard,
* Inverse obstacle scattering in two dimensions with multiple
frequency data and multiple angles of incidence, *
arXiv:1408.5436, submitted.

## 2013

C. L. Epstein, A. Kloeckner, and L. Greengard,
* On the convergence of local expansions of layer potentials, *
SIAM J. Numer. Anal., 51, 2660-2679 (2013).
A. Kloeckner, A. Barnett, L. Greengard, and M. O'Neil,
* Quadrature by expansion: a new method for the evaluation of
layer potentials, *
J. Comput. Phys., 252, 332-349 (2013).
M. O'Neil, A. Pataki, A. J. Cerfon, J. P. Freidberg, and L. Greengard,
* A fast, high-order solver for the Grad-Shafranov equation, *
submitted,
J. Comput. Phys., 243, 28-45 (2013).
F. Vico, Z. Gimbutas, L. Greengard and M. Ferrando-Bataller,
* Overcoming low-frequency breakdown of the magnetic field
integral equation, *
IEEE Trans. Antennas and Propagation, 61, 1285-1290 (2013).
Z. Liang, Z. Gimbutas, L. Greengard, J. Huang, and S. Jiang,
* A fast multipole method for the Rotne-Prager-Yamakawa tensor
and its applications, *
J. Comput. Phys., 234, 133-139 (2013).
C. L. Epstein, Z. Gimbutas, L. Greengard, A. Kloeckner, and
M. O'Neil,
* A consistency condition for the vector potential in
multiply-connected domains, *
IEEE Trans. Magnetics, 49, 1072-1076 (2013).
C. Epstein, L. Greengard and M. O'Neil,
* Debye sources and the numerical solution
of the time harmonic Maxwell equations II, *
Comm. Pure Appl. Math., 66, 753-789 (2013).
Z. Gimbutas and L. Greengard,
* Fast multi-particle scattering: a hybrid solver for the
Maxwell equations in microstructured materials, *
J. Comput. Phys., 232, 22-32 (2013).

## 2012

L. Greengard and J.-Y. Lee,
* Stable and accurate integral equation methods for scattering
problems with multiple material interfaces in two dimensions, *
J. Comput. Phys., 231, 2389-2395 (2012).
K. L. Ho and L. Greengard,
* A Fast Direct Solver for Structured Linear Systems
by Recursive Skeletonization, *
SIAM J. Sci. Comput., 35, A2507-A2532 (2012).

## 2011

F. Valdes, F. Andriulli, K. Cools, and E. Michielssen,
* A Calderon-preconditioned single source combined field integral
equation for analyzing scattering from homogeneous penetrable objects,
*
IEEE Trans. Antennas and Propagation, 59, 2315-2328 (2011).