; STOKES
;---------------------------------------------------------------
;! Stokes parameter
;# ADVERB UV
;-----------------------------------------------------------------------
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;;
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;-----------------------------------------------------------------------
;---------------------------------------------------------------
STOKES    LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
----------------------------------------------------------------
STOKES
Type:  Adverb (String*4)
Use:   Specify which Stokes parameters are to be produced or operated
       upon by a process.  Legal values depend on the task.  Normally,
       they include the Stokes parameters:
             I       Q       U       V
       the combinations of Stokes parameters:
             IV      IQU     IQUV
       the individual correlators:
             RR      LL      RL      LR
       or
             XX      YY      XY      YX
       and the combinations of correlators:
             RRLL (RR/LL)   RLLR (RL/LR)  RLRL (RR/LL/RL/LR)
       or
             XXYY (XX/YY)   XYYX (XY/YX)  XYXY (XX/YY/XY/YX)
       The generic words are interpreted differently depending on the
       polarization present in the data:
             'HALF' = RR, LL  for Stokes values > -5
                    = XX, YY  for Stokes values < -4
             'CROS' = RL, LR  for Stokes values > -5
                    = XY, YX  for Stokes values < -4
             'FULL' = I,  Q,  U,  V   for Stokes values > 0
                      RR, LL, RL, LR  for Stokes values < 0, > -5
                      XX, YY, XY, YX  for Stokes values < -4
       In many cases, it is acceptable to substitute RR or LL for I
       when the other is missing.  The code will also do this for XX
       and YY which is less likely to be correct.  If you want,
       "formal I" in which both RR and LL or XX and YY are required to
       be present change STOKES='I' to STOKES='F'.  (The F forms of
       IQU, IQUV, and IV are also accepted but they are already formal
       I in the I form.)

       WARNING: not all tasks will be able to understand this full
       range of STOKES values.  All tasks with the DOCALIB adverb
       should understand this full range, but even some of these tasks
       are more limited.  For example, IMAGR will image only one
       Stokes value at a time: I, Q, U, or V.
Null value: '    '
       Null value assignment usually means 'I' or FULL

Verbs:
   OBITIMAG......Access to OBIT task Imager without self-cal or peeling.
   OBITMAP.......Simplified access to OBIT task Imager.
   OBITPEEL......Access to OBIT task Imager with self-cal and peeling.
   OBITSCAL......Access to OBIT task Imager with self-cal, NOT peeling.
Procedures:
   LINIMAGE......Build image cube from multi-IF data set.
   MAPPR.........Simplified access to IMAGR.
   VLBACRPL......Plots crosscorrelations.
   VLBASNPL......Plots selected contents of SN or CL files.
Tasks:
   ACLIP.........Edits suto-corr data for amplitudes, phases, and weights
                 out of range.
   ALVAR.........Plots the Allan Variance statistic of a UV data set.
   ALVPR.........Prints statistics on the Allan Variance of a UV data set.
   ANBPL.........Plots and prints uv data converted to antenna based
                 values.
   APCAL.........Apply TY and GC tables to generate an SN table.
   ATMCA.........Determines delay/phase gradient from calibrator
                 observations.
   AVSPC.........Averages uv-data in the frequency domain.
   BLAPP.........Applies baseline-based fringe solutions a la BLAPP.
   BLING.........Find residual rate and delay on individual baselines.
   BLPLT.........Plots BLCAL tables in 2 dimensions as function of
                 baseline and IF.
   BPCOR.........Correct BP table.
   BPLOT.........Plots bandpass tables in 2 dimensions as function of
                 time.
   BPWGT.........Calibrates data and scales weights by bandpass
                 correction.
   BSGRD.........Task to image beam-switched single-dish data.
   CAPLT.........Plots closure amplitude and model from CC file.
   CLCOR.........Applies user-selected corrections to the calibration CL
                 table.
   CLIP..........Edits data based on amplitudes, phases, and weights out
                 of range.
   CLPLT.........Plots closure phase and model from CC file.
   CLSMO.........Smooths a calibration CL table.
   CPASS.........Computes polynomial spectral bandpass correction table.
   CSCOR.........Applies specified corrections to CS tables.
   DECOR.........Measures the decorrelation between channels and IF of uv
                 data.
   DELZN.........Determines residual atmosphere depth at zenith and clock
                 errors.
   DFCOR.........Applies user-selected corrections to the calibration CL
                 table.
   DFTIM.........Makes image of DFT at arbitrary point showing time vs
                 frequency.
   DFTPL.........Plots DFT of a UV data set at arbitrary point versus
                 time.
   EDITR.........Interactive baseline-oriented visibility editor using the
                 TV.
   ELFIT.........Plots/fits selected contents of SN, TY, SY, PC or CL
                 files.
   ELINT.........Determines and removes gain dependence on elevation.
   EVASN.........Evaluates statistics in SN/CL tables.
   EVAUV.........Subtracts & divides a model into UV data, does statistics
                 on results.
   FGCNT.........Counts samples comparing two flag tables.
   FGPLT.........Plots selected contents of FG table.
   FLAGR.........Edit data based on internal RMS, amplitudes, weights.
   FRMAP.........Task to build a map using fringe rate spectra.
   FRPLT.........Task to plot fringe rate spectra.
   FTFLG.........Interactive flagging of UV data in channel-time using the
                 TV.
   FUDGE.........Modifies UV data with user's algorithm: paraform task.
   IBLED.........Interactive BaseLine based visibility EDitor.
   IMAGR.........Wide-field and/or wide-frequency Cleaning / imaging task.
   LISTR.........Prints contents of UV data sets and assoc. calibration
                 tables.
   LOCIT.........Fits antenna locations from SN-table data.
   LPCAL.........Determines instrumental polarization for UV data.
   OMFIT.........Fits sources and, optionally, a self-cal model to uv
                 data.
   PCPLT.........Plots pulse-cal tables in 2 dimensions as function of
                 time.
   PDPLT.........Plots selected contents of PD tables.
   PLOTC.........Plots color schems used by 3-color plot tasks.
   POSSM.........Task to plot total and cross-power spectra.
   QUACK.........Flags beginning or end portions of UV-data scans.
   RFLAG.........Flags data set based on time and freq rms in fringe
                 visibilities.
   SDCAL.........Task to apply single dish calibration.
   SDGRD.........Task to select and image random-position single-dish
                 data.
   SDIMG.........Task to select and image random-position single-dish
                 data.
   SHOUV.........Displays uv data in various ways.
   SNBLP.........Plots selected contents of SN or CL files on a baseline
                 basis.
   SNCOR.........Applies user-selected corrections to the calibration SN
                 table.
   SNFIT.........Fits parabola to SN amplitudes and plots result.
   SNFLG.........Writes flagging info based on the contents of SN files.
   SNIFS.........Plots selected contents of SN, TY, SY, PC or CL files by
                 IF.
   SNPLT.........Plots selected contents of SN, SY, TY, PC or CL files
                 versus time.
   SOLCL.........Adjust gains for solar data according to nominal
                 sensitivity.
   SPFLG.........Interactive flagging of UV data in channel-TB using the
                 TV.
   SPLAT.........Applies calibration and splits or assemble selected
                 sources.
   SPLIT.........Converts multi-source to single-source UV files w
                 calibration.
   SPMOD.........Modify UV database by adding a model with spectral lines.
   SPRMS.........Plots spectral statistics of a selected subset of a uv
                 data set.
   SUFIX.........Modifies source numbers on uv data.
   SYVSN.........Plots selected SY/TY data with SN solution values versus
                 time.
   TI2HA.........Modifies times in UV data to hour angles.
   TIORD.........Checks data for time baseline ordering, displays
                 failures.
   TVFLG.........Interactive flagging of UV data using the TV.
   UFLAG.........Plots and edits data using a uv-plane grid and the TV.
   UV2MS.........Append single-source file to multi-source file.
   UV2TB.........Converts UV autocorrelation spectra to tables.
   UVCRS.........Finds the crossing points of UV-ellipses.
   UVFIL.........Create, fill a uv database from user supplied
                 information.
   UVFIT.........Fits source models to uv data.
   UVFLG.........Flags UV-data.
   UVFND.........Prints selected data from UV data set to search for
                 problems.
   UVGIT.........Fits source models to uv data.
   UVHGM.........Plots statistics of uv data files as histogram.
   UVHIM.........Makes image of the histogram on two user-chosen axes.
   UVHOL.........Prints holography data from a UV data base with
                 calibration.
   UVIMG.........Grid UV data into an "image".
   UVMAP.........Makes images from calibrated UV data.
   UVMOD.........Modify UV database by adding a model incl spectral index.
   UVPLT.........Plots data from a UV data base in multiple ways.
   UVPRM.........Measures parameters from a UV data base.
   UVPRT.........Prints data from a UV data base with calibration.
   UVRMS.........Computes statistics of a selected subset of a uv data
                 set.
   VPLOT.........Plots uv data and model from CC file.
   WIPER.........Plots and edits data from a UV data base using the TV.
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