ABS (number)

  Class:  Elemental function - Generic

  Returns the absolute value of the argument.  The absolute value of
  a complex number, (X,Y), is the real value:

      (X**2 + Y**2)**(1/2).

  +------+----------+----------+------------+-------------+
  | Args | Generic  | Specific |  Argument  | Result Type |
  +------+----------+----------+------------+-------------+
  |  1   |  ABS     |  --      | INTEGER*1  | INTEGER*1   |
  |      |          | IIABS    | INTEGER*2  | INTEGER*2   |
  |      |see note1 | IABS     | INTEGER*4  | INTEGER*4   |
  |      |          | KIABS    | INTEGER*8  | INTEGER*8   |
  |      |          | ABS      | REAL*4     | REAL*4      |
  |      |          | DABS     | REAL*8     | REAL*8      |
  |      |          | QABS     | REAL*16    | REAL*16     |
  |      |see note2 | CABS     | COMPLEX*8  | REAL*4      |
  |      |          | CDABS    | COMPLEX*16 | REAL*8      |
  |      |          | ZABS     | COMPLEX*16 | REAL*8      |
  |      |          | CQABS    | COMPLEX*32 | REAL*16     |
  +------+----------+----------+------------+-------------+

  Note1: Or JIABS.  For compatibility with older versions
         of Fortran, IABS can also be specified as a generic
         function.

  Note2: The setting of compiler options specifying real
         size can affect CABS.