SQRT intrinsic function
Standard: F77 F90 F95 F2003 F2008  Example Program
SQRT ( X )

X : Real or Complex;

Result : Same type and kind as X.
The value of the result is an approximation to the square root of X. Like many intrinsic functions, this is elemental; the result has the same shape as X, with the operation being applied elementwise.

If X is of type Real, it must be greater than or equal to zero. If X is of type Complex, the result is the principal value with the real part non-negative; if the real part of the result is zero, the imaginary part of the result has the same sign as the imaginary part of X.