AIPS HELP file for SOLTYPE in 31DEC26

As of Wed May 20 2:07:08 2026

HELP SECTION

SOLTYPE
Type:  Adverb  (string(4))
Use:   This adverb specifies the least squares solution type used in
       calibration routines.  Values used for single-pass solutions
          '    ' => normal least squares,
          'L1  ' => L1 solution,
          'GCON' => least squares which may include gain constraint
       Values for multi-pass "robust" solutions are
          'R   ' => normal least squares,
          'L1R ' => L1 solution,
          'GCOR' => least squares which may include gain constraint
       Note that all three use different mathematical methods even if
       no actual gain constraint is applied.
Null value:
       '    '   => normal least squares.

Discussion:
   Each gain solution routine does the following:
      FOR i = I1,10
          Using only unflagged data:
             find gain-set (i)
             determine deviation of data from gains = rms(i)
          Unflag the temporarily flagged data if any
          Temporarily flag any data deviating from gain-set(i)
             by > rms(i) * FF(i)
          END
   where
          FF /7., 5., 4., 3.5, 3., 2.8, 2.6, 2.4, 2.2, 2.5/
   and FF(10) may be replaced by a user-selected value.  In CALIB,
   the user selects FF(10) with DOFLAG and may choose to have the
   temporary flags generated at the last pass used to flag the data in
   a more permanent way.  I1 = 10 for non-robust methods and I1 = 1
   for the robust methods.
Tasks:
   BPASS.........Computes spectral bandpass correction table.
   CALIB.........Determines antenna calibration: complex gain.
   KRING.........Fringe fit data to determine antenna calibration,
                 delay, rate.  SOLTYPE controls what types of searches
                 are performed (FFT and/or least squares).
   PCAL..........Determines instrumental polarization for UV data.
                 SOLTYPE determines the type of polarization solved:
                 APPR, RAPR, ORI-.
   SCIMG.........Full-featured imaging plus self-calibration loop with
                 editing.
   SCMAP.........Imaging plus self-calibration loop with editing.
   SPCAL.........Determines instrumental polarization. for spectral line
                 UV data.  SOLTYPE determines what is assumed about the
                 linear polarization.
Procedures:
   IMSCAL........Large image self-cal with IM2CC and OOCAL,
   OOCAL.........Determines antenna complex gain with frequency-
                 dependent models.
   PEELR.........Calibrates interfering sources in multi-facet imges.
   VHCALIB.......Do CALIB for linear polarization with I, Q, U models.
"Verbs":
   OBITPEEL......Access to OBIT task Imager with self-cal and peeling.
                 SOLTYPE offers normal and L1 only.
   OBITSCAL......Access to OBIT task Imager with self-cal, NOT peeling
                 SOLTYPE offers normal and L1 only.

EXPLAIN SECTION