NLSstAsymptotic             package:nls             R Documentation

Fit the Asymptotic Regression Model

Description:

     Fits the asymptotic regression model, in the form `b0 +
     b1*(1-exp(-exp(lrc) * x)' to the `xy' data.   This can be used as
     a building block in determining starting estimates for more
     complicated models.

Usage:

     NLSstAsymptotic(xy)

Arguments:

      xy: a `sortedXyData' object

Value:

     A numeric value of length 3 with components labelled `b0', `b1',
     and `lrc'.  `b0' is the estimated intercept on the `y'-axis, `b1'
     is the estimated difference between the asymptote and the
     `y'-intercept, and `lrc' is the estimated logarithm of the rate
     constant.

Author(s):

     Jose Pinheiro and Douglas Bates

See Also:

     `SSasymp'

Examples:

     data( Loblolly )
     Lob.329 <- Loblolly[ Loblolly$Seed == "329", ]
     NLSstAsymptotic(sortedXyData(expression(age), expression(height), Lob.329 ))

