\Header{NLSstAsymptotic}{Fit the Asymptotic Regression Model}
\methalias{NLSstAsymptotic.sortedXyData}{NLSstAsymptotic}
\keyword{manip}{NLSstAsymptotic}
\begin{Description}\relax
Fits the asymptotic regression model, in the form \code{b0 +
      b1*(1-exp(-exp(lrc) * x)} to the \code{xy} data.  
This can be used as a building block in determining starting estimates
for more complicated models.
\end{Description}
\begin{Usage}
\begin{verbatim}
NLSstAsymptotic(xy)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{xy}] a \code{sortedXyData} object
\end{ldescription}
\end{Arguments}
\begin{Value}
A numeric value of length 3 with components labelled \code{b0},
\code{b1}, and \code{lrc}.  \code{b0} is the estimated intercept on
the \code{y}-axis, \code{b1} is the estimated difference between the
asymptote and the \code{y}-intercept, and \code{lrc} is the estimated
logarithm of the rate constant.
\end{Value}
\begin{Author}\relax
Jose Pinheiro and Douglas Bates
\end{Author}
\begin{SeeAlso}\relax
\code{\Link{SSasymp}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
data( Loblolly )
Lob.329 <- Loblolly[ Loblolly$Seed == "329", ]
NLSstAsymptotic(sortedXyData(expression(age), expression(height), Lob.329 ))
\end{ExampleCode}
\end{Examples}

