ism: Identity covariance structure

In sommer: Solving Mixed Model Equations in R

Identity covariance structure

Description

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

Usage

ism(x)

Arguments

x	Factor, character vector, numeric design, or matrix defining covariance levels.

Details

ism returns K=I. It has no covariance-shape parameters; the only unknown covariance scale is the \sigma^2 supplied by vsm. It is commonly used as the final term of vsm to indicate an independent main effect.

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(ism(id))
vsm(dsm(environment), ism(genotype))

## End(Not run)

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