Representation of the magnetization characteristic by a sum of exponentials

It is possible to set up equations of the form B(H) = a_{0} + a_{1} e^{-\alpha_{1}H} + a_{2} e^{-\alpha_{2}H} + a_{3} e^{-\alpha_{3}H} + a_{4} e^{-\alpha_{4}H} on an analog computer to fit accurately a B-H curve of any magnetic material over the whole range from zero to the knee of the curve to the saturation part of the curve.