gcc/fortran/doc/gfortran/intrinsic-procedures/abs.rst

   1 ..
   2   Copyright 1988-2022 Free Software Foundation, Inc.
   3   This is part of the GCC manual.
   4   For copying conditions, see the copyright.rst file.
   5
   6 .. _abs:
   7
   8 .. index:: ABS
   9
  10 .. index:: CABS
  11
  12 .. index:: DABS
  13
  14 .. index:: IABS
  15
  16 .. index:: ZABS
  17
  18 .. index:: CDABS
  19
  20 .. index:: BABS
  21
  22 .. index:: IIABS
  23
  24 .. index:: JIABS
  25
  26 .. index:: KIABS
  27
  28 .. index:: absolute value
  29
  30 ABS --- Absolute value
  31 **********************
  32
  33 .. function:: ABS(A)
  34
  35   ``ABS(A)`` computes the absolute value of ``A``.
  36
  37   :param A:
  38     The type of the argument shall be an ``INTEGER``,
  39     ``REAL``, or ``COMPLEX``.
  40
  41   :return:
  42     The return value is of the same type and
  43     kind as the argument except the return value is ``REAL`` for a
  44     ``COMPLEX`` argument.
  45
  46   Standard:
  47     Fortran 77 and later, has overloads that are GNU extensions
  48
  49   Class:
  50     Elemental function
  51
  52   Syntax:
  53     .. code-block:: fortran
  54
  55       RESULT = ABS(A)
  56
  57   Example:
  58     .. code-block:: fortran
  59
  60       program test_abs
  61         integer :: i = -1
  62         real :: x = -1.e0
  63         complex :: z = (-1.e0,0.e0)
  64         i = abs(i)
  65         x = abs(x)
  66         x = abs(z)
  67       end program test_abs
  68
  69   Specific names:
  70     .. list-table::
  71        :header-rows: 1
  72
  73        * - Name
  74          - Argument
  75          - Return type
  76          - Standard
  77
  78        * - ``ABS(A)``
  79          - ``REAL(4) A``
  80          - ``REAL(4)``
  81          - Fortran 77 and later
  82        * - ``CABS(A)``
  83          - ``COMPLEX(4) A``
  84          - ``REAL(4)``
  85          - Fortran 77 and later
  86        * - ``DABS(A)``
  87          - ``REAL(8) A``
  88          - ``REAL(8)``
  89          - Fortran 77 and later
  90        * - ``IABS(A)``
  91          - ``INTEGER(4) A``
  92          - ``INTEGER(4)``
  93          - Fortran 77 and later
  94        * - ``BABS(A)``
  95          - ``INTEGER(1) A``
  96          - ``INTEGER(1)``
  97          - GNU extension
  98        * - ``IIABS(A)``
  99          - ``INTEGER(2) A``
 100          - ``INTEGER(2)``
 101          - GNU extension
 102        * - ``JIABS(A)``
 103          - ``INTEGER(4) A``
 104          - ``INTEGER(4)``
 105          - GNU extension
 106        * - ``KIABS(A)``
 107          - ``INTEGER(8) A``
 108          - ``INTEGER(8)``
 109          - GNU extension
 110        * - ``ZABS(A)``
 111          - ``COMPLEX(8) A``
 112          - ``REAL(8)``
 113          - GNU extension
 114        * - ``CDABS(A)``
 115          - ``COMPLEX(8) A``
 116          - ``REAL(8)``
 117          - GNU extension