[daip] inverting flagging

[Eric Greisen]

landon at inaoep.mx writes:

 > I'm wondering if there's any way to invert the flagging that has been done on a
 > track so that everything that was flagged is now unflagged and vice-versa. If
 > there is a way, I can't find it in chapter four of the AIPS Cookbook.
 > 

That is a curious operation, why would you want to do it?

But, the short answer is that there is no such operation.  It also
depends on the current nature of the flagging.  If your data are
compressed and the flags already applied, then the data are gone and
cannot be recovered.  If the flagging is still in a flag table, then
the flag table may be ignored and/or deleted.  If the data are not
compressed, but the flagging applied, then it would be easy to write a
clone of FUDGE to do what you ask.  Flagged data have negative or 0.0
weights, unflagged data have positive weights.

Eric Greisen