R: Transforms variance components and AI matrix from gamma to...

gamma2sigma {asreml} | R Documentation

## Transforms variance components and AI matrix from gamma to sigma scale

### Description

Some of the functions (summary.asreml and vpredict) require the components and the inverse of the average information (AI) matrix to be in sigma scale. If the model is in gamma, it has to be transformed This function can be used for that purpose.

### Usage

    gamma2sigma(
      object,
      where.sigma2 = attr(is.gamma(object), "where.sigma2"),
      what = c("varcomp", "ai"),
      ...
    )

### Arguments

`object` | An `asreml` object.
`where.sigma2` | A numeric value indicating the index of the `sigma2` component in the `vparameters` object of the list object of class `asreml` (default = `attr(is.gamma(object), "where.sigma2")`).
`what` | A character vector indicating which object to obtain. Options are `varcomp` (the variance components) and `ai` (the inverse of the average information matrix) (default = `(c("varcomp", "ai"))`).
`...` | Additional arguments to asreml.options.

### Value

A list with variance components (if requested; `varcomp`) and the inverse of the AI matrix (if requested; `ai`), both in sigma scale.

### Examples

    ## Not run:
    asr.oats <- asreml(
      fixed = yield ~ Variety * Nitrogen,
      random = ~ Blocks / Wplots,
      data = oats)

    gamma2sigma(asr.oats)

    ## End(Not run)

[Package asreml version 4.2.0.480 Index]