getInitial {stats} R Documentation

## Get Initial Parameter Estimates

### Description

This function evaluates initial parameter estimates for a nonlinear regression model. If data is a parameterized data frame or pframe object, its parameters attribute is returned. Otherwise the object is examined to see if it contains a call to a selfStart object whose initial attribute can be evaluated.

### Usage

getInitial(object, data, ...)


### Arguments

 object a formula or a selfStart model that defines a nonlinear regression model data a data frame in which the expressions in the formula or arguments to the selfStart model can be evaluated ... optional additional arguments

### Value

A named numeric vector or list of starting estimates for the parameters. The construction of many selfStart models is such that these "starting" estimates are, in fact, the converged parameter estimates.

### Author(s)

José Pinheiro and Douglas Bates

nls, selfStart, selfStart.default, selfStart.formula. Further, nlsList from nlme.
PurTrt <- Puromycin[ Puromycin\$state == "treated", ]