varFunc {nlme} | R Documentation

## Variance Function Structure

### Description

If `object` is a one-sided formula, it is used as the argument to `varFixed` and the resulting object is returned. Else, if `object` inherits from class `varFunc`, it is returned unchanged.

### Usage

    varFunc(object)

### Arguments

`object` | either an one-sided formula specifying a variance covariate, or an object inheriting from class `varFunc`, representing a variance function structure.

### Value

an object from class `varFunc`, representing a variance function structure.

### Author(s)

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

### See Also

`varFixed`, `varWeights.varFunc`, `coef.varFunc`

### Examples

    vf1 <- varFunc(~age)

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