Fast Fourier Transform |
We solve the Poisson equation subject to periodic boundary conditions. The PPM FFT-based Poisson solver performs the following steps:
The data array to be transformed is optimally stored if the transformation operates along the leading dimension of the array (unit stride). Therefore, the data is transposed if necessary before performing the individual one-dimensional FFTs by using ppm pencil topologies and field mapping routines . The complete three-dimensional FFT thus consists of the following steps:
The inverse transformation involves the reverse process. |