PRIMARY /APPLY
[CLEAN\]PRIMARY [BeamSize] /APPLY Input Output [/TRUNCATE Fraction]
Attenuate the data in the Input data cube by the current primary beam and
place the result in Output. Input can be a 3-D SIC image variable or data
file, depending on the presence of a dot "." in the name. This also applies
to Output. If the later is a file, it is created. If it is a SIC variable,
it must exists and match in size the Input data.
The primary beam is recomputed to match the Input data sampling if needed.