The primary purpose of m2LL.FPBK.nodet() is to estimate the spatial
covariance parameters using REML. This is a helper function to slmfit().
m2LL.FPBK.nodet(theta, zcol, XDesign, distmat, CorModel, estmethod)is the parameter vector of (nugget, partialsill, range)
is the response vector of densities
is the design matrix containing the covariates used to predict animal or plant abundance (including a column of 1's for the intercept).
is the distance matrix of the sampled sites
is the geostatistical spatial correlation model to be used. See the corModels documentation for possible models to use.
is either "REML" for restricted maximum likelihood or "ML" for maximum likelihood.
A numeric output of minus 2 times the restricted log likelihood to be minimized by `optim` to obtain spatial parameter estimates.