An external sum log likelihoods for hyper parameters.
hsumloglike(ps, pp, prior)
a nsubject x npar matrix
a temporary pp.prior values extracted from phi. The temporary pp.prior has no attached parameter names. phi is two-element list. First element is a location array of nchain x npar x nmc; second element is a scale array of nchain x npar x nmc.
prior distributions at data level