NLSstLfAsymptote            package:stats            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:

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

