Extract Matrix or Square-Root Factor from Components of an reStruct Object

This method function extracts the positive-definite matrices corresponding to the pdMat elements of object, or square-root factors of the positive-definite matrices.

# S3 method for class 'reStruct'
pdMatrix(object, factor)

Arguments

object

an object inheriting from class "reStruct", representing a random effects structure and consisting of a list of pdMat objects.

factor

an optional logical value. If TRUE, square-root factors of the positive-definite matrices represented by the elements of object are returned; else, if FALSE, the positive-definite matrices are returned. Defaults to FALSE.

Value

a list with components given by the positive-definite matrices corresponding to the elements of object, or square-root factors of the positive-definite matrices.

References

Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer, esp. p. 162.

Author

José Pinheiro and Douglas Bates bates@stat.wisc.edu

See also

as.matrix.reStruct, reStruct, pdMat, pdMatrix, pdMatrix.pdMat

Examples

rs1 <- reStruct(pdSymm(diag(3), ~age+Sex, data = Orthodont))
pdMatrix(rs1)
#> [[1]]
#>             (Intercept) age SexFemale
#> (Intercept)           1   0         0
#> age                   0   1         0
#> SexFemale             0   0         1
#>