We present a second-order accurate algorithm for solving the free-space Poisson’s
equation on a locally-refined nested grid hierarchy in three dimensions. Our approach
is based on linear superposition of local convolutions of localized charge distributions,
with the nonlocal coupling represented on coarser grids. The representation of the
nonlocal coupling on the local solutions is based on Anderson’s Method of Local
Corrections and does not require iteration between different resolutions. A
distributed-memory parallel implementation of this method is observed to have a
computational cost per grid point less than three times that of a standard FFT-based
method on a uniform grid of the same resolution, and scales well up to 1024
processors.
Keywords
Poisson's equation, local corrections, domain
decomposition, adaptive mesh refinement