(the
order in which the parameters are included is detailed in <code>details</code>
section).  (2) nothing is specified. A preliminary analysis involving the
estimation of a standard linear mixed model is performed to choose initial
values.  (3) when ng&gt;1, a hlme object is entered. It should correspond to
the exact same structure of model but with ng=1. The program will
automatically generate initial values from this model. This specification
avoids the preliminary analysis indicated in (2). Note that du