Hard-coded functions, representing (runtime) S4-based function objects.
DO NOT CALL THESE FUNCTIONS. CALL A CONSTRUCTOR, WHICH SHOULD RETURN A FUNCTION OBJECT.
kub.function.object (x)
A numeric vector (or array), giving the evaluation points. This can include nonfinite values.
All function objects return a numeric vector (or numeric array).
The dimensions of the input, determine the dimensions of the output.