  Fourier and related transforms is a family of algorithms widely employed in
diverse areas of computational science, notoriously difficult to scale on
high-performance parallel computers with large number of processing elements
(cores). This paper introduces a popular software package called P3DFFT
implementing Fast Fourier Transforms (FFT) in three dimensions (3D) in a highly
efficient and scalable way. It overcomes a well-known scalability bottleneck of
3D FFT implementations by using two-dimensional domain decomposition. Designed
for portable performance, P3DFFT achieves excellent timings for a number of
systems and problem sizes. On Cray XT5 system P3DFFT attains 45% efficiency in
weak scaling from 128 to 65,536 computational cores. Library features include
Fourier and Chebyshev transforms, Fortran and C interfaces, in- and
out-of-place transforms, uneven data grids, single and double precision. P3DFFT
is available as open source at http://code.google.com/p/p3dfft/. This paper
discusses P3DFFT implementation and performance in a way that helps guide the
user in making optimal choices for parameters of their runs.

Distributed, Parallel, and Cluster Computing;Mathematical Software