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AIPS HELP file for SOLTYPE in 31DEC22

#### As of Tue Feb 7 13:59:55 2023

### 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.
"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