Algorithm 651: Algorithm HFFT-high-order fast-direct solution of the Helmholtz equation

@article{Boisvert1987Algorithm6A,
  title={Algorithm 651: Algorithm HFFT-high-order fast-direct solution of the Helmholtz equation},
  author={Ronald F. Boisvert},
  journal={ACM Trans. Math. Softw.},
  year={1987},
  volume={13},
  pages={235-249}
}
HFFT is a software package for solving the Helmholtz equation on bounded two- and three-dimensional rectangular domains with Dirichlet, Neumann, or periodic boundary conditions. The software is the result of combining new fourth-order accurate compact finite difference (HODIE) discretizations and a fast-direct solution technique (the Fourier method). In this paper we briefly describe the user interface to HFFT and present an example of its usage and several details of its implementation.