Gibbs update for dyadic variance

rs2_fc(Z, rho,offset=0,nu0=NULL,s20=NULL)

Arguments

Z	n X n normal relational matrix
rho	current value of rho
offset	matrix of the same dimension as Z. It is assumed that Z-offset is equal to dyadic noise, so the offset should contain any additive and multiplicative effects (such as `Xbeta(X,beta+ U%*%t(V) + outer(a,b,"+")` )
nu0	prior degrees of freedom
s20	prior estimate of s2

a new value of s2

Peter Hoff