R: Get Initial Parameter Estimates

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

### See Also

`nls`, `selfStart`, `selfStart.default`, `selfStart.formula`. Further, `nlsList` from nlme.

### Examples

    PurTrt <- Puromycin[ Puromycin$state == "treated", ]
    print(getInitial( rate ~ SSmicmen( conc, Vm, K ), PurTrt ), digits = 3)

[Package stats version 3.5.1 Index]