Find the initial values of kappa2 and phi
.initialKP(theta, spde, w, n_sess, tol, verbose)
a vector of length two containing the range and scale parameters kappa2 and phi, in that order
a list containing the sparse matrix elements Cmat, Gmat, and GtCinvG
the beta_hat estimates for a single task
the number of sessions
the stopping rule tolerance
(logical) Should intermediate output be displayed?