This string parameter can be set either to
Logarithmic. In the first case, the zone radial width is a constant over the whole disk (i.e. the zone interface radii are in arithmetic sequence), while in the second case, the zone radial width is proportional to its distance to the mesh center (the zone interface radii are in geometric sequence). In this last case, all zones have the same aspect ratio (azimuthal over radial width).
NRAD+1 interface radii are written in an ASCII file named
used_rad.dat in the output directory (specified by
OutputDir). Note that it is possible to have an arbitrary sequence of interface radii, more complex than an arithmetic or geometric sequence, for instance if you need a high resolution in the vicinity of a planet orbit. In order to do that, you need to create, prior to the run execution, a file named
radii.dat in the output directory. This file must be in ASCII format, and must contain a column of floating point values representing the
NRAD+1 interface radii, in increasing order. Once the run is started, the
used_rad.dat file is created. One can check that
radii.dat has properly been read by checking that
used_rad.dat contains the same values.