Estimate the conditional expectation for a STAR process under the log link function.
expectation_log(a, Jmax, Mu, sigma_t, Offset)Zhat T x m matrix of conditional expectations
Jmaxmax-dimensional vector of STAR integers a_j
T x m matrix of maximum integer values to consider
T x m matrix of latent means
T-dimensional vector of time-dependent latent error sd's
T x m matrix of offsets