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^(+Number1, +Number2, -Result)

Evaluates the expression Number1 "to the power of" Number2 and unifies the resulting value with Result.
Number1
A number.
Number2
A number.
Result
A variable or a number.

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

Exceptions

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

Examples

Success:
      ^(5, 3, 125).
      ^(-5, 3, -125).
      ^(5, -2, 0.04).

      ^(5, 2.2, 34.493244).
      ^(5.0, 2, 25.0).
      ^(-5.0, 3, -125.0).
      ^(0.0, 12.3, 0.0).
      ^(3.3, 0.0, 1.0).
      ^(0.0, 0.0, 1.0).
Fail:
      ^(1, 2, 3).
      ^(1, 2, 3.0).
      ^(5, 2, r).
Error:
      ^(A, 2, 6).             (Error 4).
      ^(-5, 0.5, X).          (Error 20).
      ^(-5.0, 3.1, X).        (Error 20).
      ^(2 + 3, 2, 25).        (Error 24).



See Also

is / 2, get_flag / 2, set_flag / 2