X is a vector/scalar which must be 16-byte data type.
It returns the lower 8 bytes of X, which is of DOUBLE type.
$ $ x=1 2 3 4 $ y=4 3 2 1 $ points = point(x, y) $ x1 = lowDouble(points) [1,2,3,4]
Get the real part of the complex number:
$ a=complex(2, 5) $ lowDouble(a) 2