The Fieldconvert range option -r allows the user to specify a sub-range of the mesh
(computational domain) by using an additional flag, -r (which stands for range and either
convert or manipulate the Nektar++ output binary files. Taking as an example the conversion
of the Nektar++ binary files (.chk or .fld) shown before and wanting to convert just the 2D
sub-range defined by −2 ≤ x ≤ 3, −1 ≤ y ≤ 2 the additional flag -r can be used as follows:
where -r defines the range option of the FieldConvert utility, the two first numbers
define the range in x direction and the the third and fourth number specify the y
range. A sub-range of a 3D domain can also be specified. For doing so, a third set of
numbers has to be provided to define the z range.