NLSstLfAsymptote             package:nls             R Documentation

Horizontal Asymptote on the Left Side

Description:

     Provide an initial guess at the horizontal asymptote on the left
     side (i.e. small values of `x') of the graph of `y' versus `x'
     from the `xy' object.  Primarily used within `initial' functions
     for self-starting nonlinear regression models.

Usage:

     NLSstLfAsymptote(xy)

Arguments:

      xy: a `sortedXyData' object

Value:

     A single numeric value estimating the horizontal asymptote for
     small `x'.

Author(s):

     Jose Pinheiro and Douglas Bates

See Also:

     `sortedXyData', `NLSstClosestX', `NLSstRtAsymptote', `selfStart'

Examples:

     data( DNase )
     DNase.2 <- DNase[ DNase$Run == "2", ]
     DN.srt <- sortedXyData( expression(log(conc)), expression(density), DNase.2 )
     NLSstLfAsymptote( DN.srt )

