[ Arithmetic | Reference Manual | Alphabetic Index ]

sqrt(+Number, -Result)

Evaluates the square root sqrt(Number) and unifies the resulting value with Result.
Number
A number.
Result
Output: float or breal.

Description

This predicate is used by the ECLiPSe compiler to expand evaluable arithmetic expressions. So the call to sqrt(Number, Result) is equivalent to 
    Result is sqrt(Number)
which should be preferred for portability.

In coroutining mode, if Number is uninstantiated, the call to sqrt/2 is delayed until this variable is instantiated.

Modes and Determinism

Exceptions

(4) instantiation fault
Number is not instantiated (non-coroutining mode only).
(24) number expected
Number is not of a numeric type.
(20) arithmetic exception
Illegal arithmetic operation: Number is negative.

Examples

Success:
    Result is sqrt(2.0).	% gives Result = 1.4142135623730951
    Result is sqrt(1.0).      	% gives Result = 1.0
    Result is sqrt(49).       	% gives Result = 7.0

Error:
    Result is sqrt(-2).         % arithmetic exception

See Also

is / 2