Draw the dyadic residual variance s2 from its inverse-gamma full
conditional. The residual matrix E = Z - offset is decorrelated
within reciprocal dyad pairs and along the diagonal, and the pooled sum of
squares (together with an optional scaled-inverse-chi-square prior) yields
the posterior draw.
Arguments
- Z
n x n normal relational matrix
- rho
current within-dyad correlation
- offset
matrix conformable with
Z;Z - offsetis treated as pure dyadic noise (so it should carry the additive and multiplicative mean structure)- nu0
prior degrees of freedom (defaults to 1)
- s20
prior scale for s2; when
NULLthe empirical mean of the decorrelated squared residuals is used so the prior sits at the data scale