; DOUVCOMP
;---------------------------------------------------------------
;! selects use of compression in writing UV data to disk
;# ADVERB UV
;-----------------------------------------------------------------------
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;;  Associated Universities, Inc. Washington DC, USA.
;;
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;;
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;;         Postal address: AIPS Project Office
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;-----------------------------------------------------------------------
DOUVCOMP  LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
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DOUVCOMP
Type: Adverb (Logical: <= 0 is false, > 0 is true)
Use:  Instructs tasks to write visibility data to disk in AIPS
      compressed format.  This format has one correlator value (2
      numbers) per floating word, magic value blanking, and a single
      weight per visibility record.  This may result in a significant
      reduction in disk usage (up to a factor of 3).  This comes at a
      cost - the data must be compressed and uncompressed as they are
      used which requires a multiply for every datum.  There is only one
      weight for all IFs and polarizations which probably does not
      represent reality (even if all spectral channels do have the same
      weight).  Furthermore, the full dynamic range of the numbers is 1
      in 32768 which means that one bad value can turn all the rest of
      the numbers into pure 0.
Null value:  false (-1)
Tasks:
   ATLOD.......Reads ATCA data in RPFITS dormat into AIPS.
   BLING.......Find residual rate and delay on individual baselines.
               DOUVCOMP refers to the format of scratch files.
   FILLM.......Reads VLA on-line/archive format uv data tapes (post Jan
               88).
   FITAB.......Writes images / uv data w extensions to tape in FITS
               format.  DOUVCOMP refers to the format in the output
               FITS UV table.
   FITLD.......Reads FITS files to load images or UV (IDI or UVFITS)
               data to disk.  DOUVCOMP does not apply to input UV FITS
               tables.
   FIXWT.......Modify weights to reflect amplitude scatter of data.
   M3TAR.......Translate Haystack MKIII VLBI format "A" TAR's into
               AIPS.
   MK3IN.......Translate Haystack MKIII VLBI format "A" tapes into
               AIPS.
   OTFUV.......Translates on-the-fly single-dish SDD format to AIPS UV
               file.
   SPLAT.......Applies calibration and splits or assemble selected
               sources.
   SPLIT.......Converts multi-source to single-source UV files w
               calibration.
   UV2MS.......Append single-source file to multi-source file.
   UVLOD.......Read export or FITS data from a tape or disk.
   VLBIN.......Task to read VLBI data from an NRAO/MPI MkII correlator.
"Verbs":
   BDF2AIPS....Read EVLA ASDM/BDF data into AIPS.
Procedures:
   READISK.....Reads images / uv data w extensions in FITS format into
               AIPS.
   VLBALOAD....Loads VLBA data.
   VLBAMPHC....Applies VLBARUN calibration to additional phase stopping
               centers.  DOUVCOMP is used only if data have to be
               loaded.
   VLBARUN.....Applies amplitude and phase calibration procs to VLBA
               data.  The VLBA calibration, editing, imaging pipeline.
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