Guess the horizontal asymptote on the left side

Usage

NLSstLfAsymptote(xy)

Arguments

xy a sortedXyData object

Description

This function provides an initial guess at the horizontal asymptote on the left side (smaller values of x) of the graph of y versus x from the xy object. It is mostly used within the initial functions for a self-starting nonlinear regression models, which are in the selfStart class.

Value

A single numeric value which is a guess at the y value that would be the asymptote for small x.

Author(s)

Jose Pinheiro and Douglas Bates

Examples

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

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