Initialize.varFunc {nlme} | R Documentation

## Initialize varFunc Object

### Description

This method initializes `object` by evaluating its associated covariate(s) and grouping factor, if any is present, in `data`; determining if the covariate(s) need to be updated when the values of the coefficients associated with `object` change; initializing the log-likelihood and the weights associated with `object`; and assigning initial values for the coefficients in `object`, if none were present. The covariate(s) will only be initialized if no update is needed when `coef(object)` changes.

### Usage

    ## S3 method for class 'varFunc':
    Initialize(object, data, ...)

### Arguments

`object` | an object inheriting from class `varFunc`, representing a variance function structure.
`data` | a data frame in which to evaluate the variables named in `formula(object)`.
`...` | this argument is included to make this method compatible with the generic.

### Value

an initialized object with the same class as `object` representing a variance function structure.

### Author(s)

Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu

### Examples

    data(Orthodont)
    vf1 <- varPower( form = ~ age | Sex )
    vf1 <- Initialize( vf1, Orthodont )

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