source 2008 Bernstein--Lange--Rezaeian Farashahi parameter d2overd1plus1 assume d2overd1plus1 = d2/d1 + 1 compute R = w2 w3 compute S = R^2 compute T = R(1+w2+w3)+S compute w5 = T/(d1+T+d2overd1plus1 S)+w1 compute A = w2^2 compute J = A^2 compute K = A+J compute w4 = K/(d1+K+d2overd1plus1 J)