###### Description

asv.asreml computes the approximate stratum variances, degrees of freedom and coefficients for simple variance component models.

###### Usage

## S3 method for class 'asreml' asv(object, order = c("as.is", "noeff"), vvp = FALSE, ...)

###### Arguments

`object` |
An object of class `asreml` . |

`order` |
The sequence in which to consider the random terms: may be one of “`as.is` ” or “`noeff` ” for the order as given in the `asreml` object, or ordered by increasing number of effects, respectively. The default is “`as.is` “. Note that the default ordering for random terms in asreml is “`noeff` “. |

`vvp` |
If `TRUE` (the default is `FALSE` ) the inverse of the average information matrix for the variance components (sigma scale) is returned. |

… |
Any additional arguments. |

###### Details

Approximate stratum variances and degrees of freedom for simple variance components models are returned. For the linear mixed-effects model, it is often possible to consider a natural ordering of the variance component parameters, including the residual. Based on an idea due to *Thompson, 1980*, `asreml`

computes approximate stratum degrees of freedom and stratum variances by a modified Cholesky diagonalisation of the average information matrix.

###### Value

If `vvp`

is `FALSE`

, a rectangular matrix containing the degrees of freedom, approximate variances and the component coefficients for each random term. If `vvp`

is `TRUE`

, a list of length two containing the matrix of approximate stratum variances and the inverse average information matrix of the variance components in list components `asv`

and `vvp`

, respectively.

###### References

Thompson R (1980). “Maximum likelihood estimation of variance components.” *Series Statistics*, **11**(4), pp. 545-561.