AIPS NRAO AIPS HELP file for DOUVCOMP in 31DEC18



As of Sat Jun 23 2:27:07 2018



HELP SECTION

DOUVCOMP
Type: Adverb (Logical: <= 0 is false, > 0 is true)
Use:  Instructs tape reading programs 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)

EXPLAIN SECTION


AIPS