] and i ̸ = n,) and cE 0 n = 1, and the focusing label n is stochastically chosen with the probability P (n) = µ n /( N m=1 µ m ) and initialize c G 0 = cE 0 n = 1. The first term in Eq. 66 can be computed using the following steps 1. Sample the nuclear configuration based on [ρ b ] w .