AIPS HELP file for FUNCTYPE in 31DEC09

As of Sun Nov 22 16:51:19 2009

HELP SECTION

FUNCTYPE
Type: Adverb (String, 2 characters)
Use:  The function type associated with a task or a verb.  The function
      is designated by two characters.
      For image loading transfer functions the usual values are
         'LN' for linear,                 -> x
         'LG' for logarithmic,            -> log10 (1+9*x)
         'L2' for extra logarithmic       -> log10 (1+99*x) / 2
         'SQ' for square root,            -> sqrt (x)
         'NE' for negative linear,        -> 1 - x
         'NG' for negative logarithmic,   -> log10 (10 - 9*x)
         'N2' for negative extra logarithmic -> log10 (100-99*x) / 2
         'NQ' for negative square root.   -> sqrt (1-x)
      where x is between 0 and 1 and is usually taken from
          x = (Map(i,j) - Pixr(1)) / (Pixr(2) - Pixr(1))
          x = max (0, min (1, x))
      Unrecognized codes are taken as 'LN'.
Null value: '  '
      Null value assignment varies with task or verb.

EXPLAIN SECTION