ASeff finds the constant c which is associated to the requested efficiency for Andrew's sine function
ceff=ASeff(eff, v)
example
Andrews, D.F., Bickel, P.J., Hampel, F.R., Huber, P.J., Rogers, W.H., and Tukey, J.W. (1972), "Robust Estimates of Location: Survey and Advances", Princeton Univ. Press, Princeton, NJ. [p. 203]
Andrews, D. F. (1974). A Robust Method for Multiple Linear Regression, "Technometrics", V. 16, pp. 523-531, https://doi.org/10.1080/00401706.1974.10489233
Riani, M., Cerioli, A. and Torti, F. (2014), On consistency factors and efficiency of robust S-estimators, "TEST", Vol. 23, pp. 356-387, http://dx.doi.org/10.1007/s11749-014-0357-7