Return the mapping parameters.
The returned values define a linear map off + scl*x that is applied to the input arguments before the series is evaluated. The map depends on the domain and window; if the current domain is equal to the window the resulting map is the identity. If the coefficients of the series instance are to be used by themselves outside this class, then the linear function must be substituted for the x in the standard representation of the base polynomials.
off, scl : float or complex
The mapping function is defined by off + scl*x.
If the current domain is the interval [l1, r1] and the window is [l2, r2], then the linear mapping function L is defined by the equations:
L(l1) = l2 L(r1) = r2