Description Usage Arguments Value Author(s) References See Also Examples

This function is a constructor for the `varPower`

class,
representing a power variance function structure. Letting
*v* denote the variance covariate and *s2(v)*
denote the variance function evaluated at *v*, the power
variance function is defined as *s2(v) =
|v|^(2*t)*, where *t* is the variance
function coefficient. When a grouping factor is present, a different
*t* is used for each factor level.

1 | ```
varPower(value, form, fixed)
``` |

`value` |
an optional numeric vector, or list of numeric values,
with the variance function coefficients. |

`form` |
an optional one-sided formula of the form |

`fixed` |
an optional numeric vector, or list of numeric values,
specifying the values at which some or all of the coefficients in
the variance function should be fixed. If a grouping factor is
specified in |

a `varPower`

object representing a power variance function
structure, also inheriting from class `varFunc`

.

José Pinheiro and Douglas Bates [email protected]

Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer.

`varWeights.varFunc`

,
`coef.varPower`

1 | ```
vf1 <- varPower(0.2, form = ~age|Sex)
``` |

```
```

nlme documentation built on April 7, 2018, 5:03 p.m.

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.