Output

For 3D data, output is in 3D format that can be read with read3d.pro, e.g.,

IDL> a = read3d()

The binary file format starts out with the array size nx, ny, nz. The next parameter is the IDL_data_type. After that, the file contains a stream of $\texttt{nx} \times \texttt{ny} \times \texttt{nz}$ data pixels of type IDL_data_type.

read3d.pro contains options to read other types of 3D data file, for example slab decomposition of data output by MPI reconstruction code, and general subregions of a larger cube. The output of Xewald is the simplest data format.

For 2D slices through $k_{z}=0$, two files are output:

1. The slice is output as a binary GRID file that can be read by read_grid.pro:

   IDL> a = read_grid()
   

   This is a legacy file format that I won't explain further here$\ldots$
2. Also output is a 3D slab of data from $\pm 3$ pixels either side of $k_{z}=0$, in the 3D format described above. This is to allow you to do your own interpolation or data filling based on what happens either side of $k_{z}=0$.