dsm: Diagonal heterogeneous covariance structure

In sommer: Solving Mixed Model Equations in R

Diagonal heterogeneous covariance structure

Description

Diagonal heterogeneous covariance structure. The returned dimensionless covariance shape is intended for use inside vsm, which supplies the single overall variance scale.

Usage

dsm(x, values = NULL, fixed = NULL, theta = NULL)

Arguments

x	Variable or design defining the covariance levels.
values	Optional positive starting variances, one per level.
fixed	Logical vector of length q-1 indicating which variance-ratio parameters are fixed.
theta	Optional q by q diagonal starting covariance matrix; if supplied, its diagonal replaces values.

Details

For q levels, dsm uses the first variance as the internal scale reference and estimates q-1 positive variance ratios,

K=\mathrm{diag}(1,r_2,\ldots,r_q).

The ratios are optimized on log scales and reported on their natural positive scale.

Value

A list containing the incidence/design matrix in Z and a compiled CovarianceFactor v2 descriptor in covFactor, for use inside vsm.

See Also

vsm, mmes.

Examples

## Not run: 
vsm(dsm(environment), ism(genotype))

## End(Not run)

sommer documentation built on Oct. 25, 2026, 5:06 p.m.