
^(+Number1, +Number2, -Result)

   Evaluates the expression Number1 "to the power of" Number2 and unifies the
resulting value with Result.



Arguments
   Number1             A number.
   Number2             A number.
   Result              Output: a number.

Type
   Arithmetic

Description
   This predicate is used by the ECLiPSe compiler to expand evaluable
   arithmetic expressions.  So the call to ^(Number1, Number2, Result) is
   equivalent to

    Result is Number1 ^ Number2

    which should be preferred for portability.

   The result is of type float if any of the arguments is a float. 
   When an integer is raised to the power of a negative integer, the
   result type depends on the value of the global flag prefer_rationals.
   If it is on, it is a rational, otherwise a float.  When the exponent
   is not an integer, the result is of type float.


   In coroutining mode, if Number1 or Number2 are uninstantiated, the call
   to ^/3 is delayed until these variables are instantiated.




Modes and Determinism
   ^(+, +, -) is det

Exceptions
     4 --- Number1 or Number2 is not instantiated (non-coroutining mode    only).
    24 --- Number1 or Number2 is not of a numeric type.
    20 --- Illegal arithmetic operation:  Number1 is negative and    Number2 is no integral number.
    20 --- Illegal arithmetic operation:  Number1 and Number2 are both    zero.

Examples
   
Success:
    Result is 5 ^ 3.		% gives Result = 125
    Result is -5 ^ 3.		% gives Result = -125
    Result is 5 ^ -2.		% gives Result = 0.04

    Result is 5 ^ 2.2.		% gives Result = 34.493244
    Result is 5.0 ^ 2.		% gives Result = 25.0
    Result is -5.0 ^ 3.		% gives Result = -125.0
    Result is 0.0 ^ 12.3.	% gives Result = 0.0
    Result is 3.3 ^ 0.0.	% gives Result = 1.0
    Result is 0.0 ^ 0.0.	% gives Result = 1.0

Error:
    Result is -5 ^ 0.5.         % arithmetic exception
    Result is -5.0 ^ 3.1.       % arithmetic exception


See Also
   is / 2, get_flag / 2, set_flag / 2
