nadiv (version 2.7)

aiFun: Sampling (co)variances and correlations of random terms

Description

This function returns the sampling covariances, variances, and correlations of the random effects fitted in an ASReml-R model

Usage

aiFun(model, Dimnames = NULL)

Arguments

model

A model object returned by a call to the asreml function.

Dimnames

A vector of characters if names are desired for the (co)variance/correlation matrix.

Value

• A matrix of k x k dimensions is returned, if k is the number of random effects estimated in the model. If Dimnames is specified, the row and column names are assigned according the vector of names in the argument.

Details

The inverse of the average information provides the sampling (co)variance of each random term in the mixed model. This function extracts the AI matrix from an ASReml-R model and organizes it so that the sampling covariances between random terms are located below the diagonal, the sampling variances of random terms are located along the diagonal, and the sampling correlations between random terms are located above the diagonal. The order of the variances along the diagonal is the same as the order entered in the random section of the asreml function. This is the same order as the rows of a call to the summary function, summary(model)$varcomp.

References

Gilmour, A.R., Gogel, B.J., Cullis, B.R., & Thompson, R. 2009. ASReml User Guide Release 3.0. VSN International Ltd., Hemel Hempstead, UK.

Examples

library(asreml)
    ginvA <- asreml.Ainverse(warcolak)$ginv
    ginvD <- makeD(warcolak[,1:3])$listDinv
    warcolak$IDD <- warcolak$ID
    warcolak.mod <- asreml(phenotype ~ 1, random = ~ped(ID) + giv(IDD), ginverse = list(ID = ginvA, IDD = ginvD), data = warcolak) 
    summary(warcolak.mod)$varcomp
    aiFun(warcolak.mod, Dimnames = c("Va", "Vd", "Ve"))