nlme.control
a list of control parameters for the nonlinear regression step,
the same as nlmeControl. Default is list(returnObject = T, maxIter = 5)
.
converg
an optional character, with possible values "COEF" and "PRSS", specifying the convergence
criterion to be used. "COEF" uses the change of estimate of parameters and functions to
assess convergence, and "PRSS" uses penalized residual sums of squares. De